Methods of delivery of flexible heart valves

ABSTRACT

A prosthetic heart valve can include a valve frame having a wireform portion and a stent portion. The wireform and stent portions can be undetachably coupled together via a plurality of upright struts so as to form a one-piece prosthetic heart valve frame. Alternatively, a self-expanding wireform portion and a balloon-expandable stent portion can be coupled together via one or more leaflets and a subassembly having a flexible leaflet support stent and a sealing ring. The wireform portion can include cusps and commissures configured to support a plurality of leaflets. The prosthetic valve can be radially collapsible for minimally invasive and/or transcatheter delivery techniques. Disclosed embodiments can also provide flexion of the wireform portion (e.g., of the commissures) in response to physiologic pulsatile loading when the valve is implanted in a patient&#39;s native valve annulus. Methods of making and using prosthetic heart valves are also disclosed.

RELATED APPLICATIONS

The present application is a divisional of U.S. application Ser. No.13/237,556, filed Sep. 20, 2011, which in turn claims priority under 35U.S.C. §119 to U.S. Provisional Application Ser. No. 61/386,833, filedSep. 27, 2010, and Provisional Application Ser. No. 61/472,083, filedApr. 5, 2011, all of which are incorporated by reference herein in theirentirety.

FIELD OF THE INVENTION

The present invention concerns implantable prosthetic valves and valveframes, and related methods and systems, such as for example, prostheticaortic valves that can be implanted using minimally invasive surgicaltechniques.

BACKGROUND OF THE INVENTION

In vertebrate animals, the heart is a hollow muscular organ having fourpumping chambers as seen in FIG. 1: the left and right atria and theleft and right ventricles, each provided with its own one-way valve. Thenatural heart valves are identified as the aortic, mitral (or bicuspid),tricuspid, and pulmonary, and are each mounted in an annulus comprisingdense fibrous rings attached either directly or indirectly to the atrialand ventricular muscle fibers. Each annulus defines a flow orifice.

The atria are the blood-receiving chambers, which pump blood into theventricles. The ventricles are the blood-discharging chambers. A wallcomposed of fibrous and muscular parts, called the interatrial septumseparates the right and left atriums (see FIGS. 2, 3 and 4). The fibrousinteratrial septum is a materially stronger tissue structure compared tothe more friable muscle tissue of the heart. An anatomic landmark on theinteratrial septum is an oval, thumbprint sized depression called theoval fossa, or fossa ovalis (shown in FIG. 4).

The synchronous pumping actions of the left and right sides of the heartconstitute the cardiac cycle. The cycle begins with a period ofventricular relaxation, called ventricular diastole. The cycle ends witha period of ventricular contraction, called ventricular systole. Thefour valves (see FIGS. 2 and 3) ensure that blood does not flow in thewrong direction during the cardiac cycle; that is, to ensure that theblood does not back flow from the ventricles into the correspondingatria, or back flow from the arteries into the corresponding ventricles.The mitral valve is between the left atrium and the left ventricle, thetricuspid valve between the right atrium and the right ventricle, thepulmonary valve is at the opening of the pulmonary artery, and theaortic valve is at the opening of the aorta.

FIGS. 2 and 3 show the anterior (A) portion of the mitral valve annulusabutting the non-coronary leaflet of the aortic valve. The mitral valveannulus is in the vicinity of the circumflex branch of the left coronaryartery, and the posterior (P) side is near the coronary sinus and itstributaries.

The mitral and tricuspid valves are defined by fibrous rings ofcollagen, each called an annulus, which forms a part of the fibrousskeleton of the heart. The annulus provides peripheral attachments forthe two cusps or leaflets of the mitral valve (called the anterior andposterior cusps) and the three cusps or leaflets of the tricuspid valve.The free edges of the leaflets connect to chordae tendinae from morethan one papillary muscle, as seen in FIG. 1. In a healthy heart, thesemuscles and their tendinous chords support the mitral and tricuspidvalves, allowing the leaflets to resist the high pressure developedduring contractions (pumping) of the left and right ventricles.

When the left ventricle contracts after filling with blood from the leftatrium, the walls of the ventricle move inward and release some of thetension from the papillary muscle and chords. The blood pushed upagainst the under-surface of the mitral leaflets causes them to risetoward the annulus plane of the mitral valve. As they progress towardthe annulus, the leading edges of the anterior and posterior leafletcoapt and form a seal, closing the valve. In the healthy heart, leafletcoaptation occurs near the plane of the mitral annulus. The bloodcontinues to be pressurized in the left ventricle until it is ejectedinto the aorta. Contraction of the papillary muscles is simultaneouswith the contraction of the ventricle and serves to keep healthy valveleaflets tightly shut at peak contraction pressures exerted by theventricle. The remaining cardiac valves operate in a similar fashion.

Various surgical techniques may be used to repair a diseased or damagedvalve. In a valve replacement operation, the damaged leaflets aretypically excised and the annulus sculpted to receive a prostheticvalve. Due to aortic stenosis and other heart valve diseases, thousandsof patients undergo surgery each year wherein the defective native heartvalve is replaced by a prosthetic valve (either bioprosthetic ormechanical). Another, less drastic, method for treating defective valvesis through repair or reconstruction, which is typically used onminimally calcified valves. One problem with surgical therapy is thesignificant insult it imposes on chronically ill patients and theassociated high morbidity and mortality rates associated with surgicalrepair.

When a valve is replaced, surgical implantation of the prosthetic valvehas typically required an open-chest surgery, during which the heart isstopped and the patient is placed on cardiopulmonary bypass (a so-called“heart-lung machine”). In one common surgical procedure, the diseasednative valve leaflets are excised and a prosthetic valve is sutured tothe surrounding tissue of the valve annulus. Because of the traumaassociated with the procedure and the attendant duration ofextracorporeal blood circulation, mortality rates during surgery orshortly thereafter typically have been high. It is well established thatrisks to patients increase with the duration of extracorporealcirculation. Due to such risks, a substantial number of patients withdefective valves are deemed inoperable because their condition is toofrail to withstand the procedure. By some estimates, up to about 50% ofpatients suffering from aortic stenosis and who are older than 80 yearscannot undergo surgery for aortic valve replacement using conventionalopen-chest surgery.

Because of drawbacks associated with conventional open-heart surgery,percutaneous and minimally-invasive surgical approaches are garneringintense attention. Minimally invasive surgical techniques have been andcontinue to be developed. In successfully performed minimally invasivetechniques, a conventional sternotomy can be avoided. Access to theheart can be by way of upper sternotomy or thoracotomy allowing asmaller incision and typically shorter healing times, as well as lesspain for the patient. Blood loss is typically lower with minimallyinvasive techniques, hospital stays are shorter, and there may be lowermorbidity and mortality rates as compared to conventional surgicaltechniques.

To obtain at least some of the potential benefits of the smallerincisions required by minimally invasive surgical techniques, prostheticvalves compatible with such techniques are needed. For instance, U.S.Pat. No. 5,411,522 to Andersen et al. describes a collapsible valvepercutaneously introduced in a compressed state through a catheter andexpanded in the desired position by balloon inflation.

In another approach, a flexible heart valve especially suitable forimplanting in the aortic annulus has been proposed in U.S. Pat. No.6,558,418 to Carpentier, et al., and U.S. Pat. No. 6,736,845 to Marquez,et al. More particularly, Carpentier and Marquez disclose single andmulti-element wireform assemblies that include flexible cusps betweenadjacent commissure portions extending therefrom. A suture-permeableconnecting band attached to the disclosed prosthetic valve follows theshape of (i.e., is coextensive with) the underlying frame. In theCarpentier and Marquez approach, the valve is secured by attaching(e.g., suturing) the connecting band (and thereby, the entire contour ofthe underlying frame, including the cusp and commissure portions) to thesurrounding natural tissue. Although this approach represents anadvancement of surgically implantable valves, the commissure portions ofthe frame remain fixedly attached to, and cannot move independently of,the tissue because the sewing band is coextensive with the undulatingframe. In addition, suturing the complex, undulating periphery of thesewing band can be difficult and time consuming, as various parts of thevalve can interfere with access to the sewing band. Although the valvesdisclosed in the '418 and '845 patents could be collapsed and insertedthrough a small incision, such as a thoracotomy, it would be difficultto suture them to the native annulus through such a small incision dueto the configuration of the sewing band.

Conventional surgical valves have long-term durability, due in part tothe flexibility of the valve structure, which allows the valve to flexslightly during physiologic loading. However, these surgical valvesdisadvantageously cannot be radially collapsed any appreciable amount,and therefore are not suitable for minimally invasive surgeryprocedures. Conventional surgical valves also require suturing to securethe valve to a patient's annulus. Such suturing can be disadvantageousin that it is time consuming and difficult, thus extending the length ofsurgery.

One heart valve designed to provide a faster method of securing theprosthetic valve to a patient's annulus is disclosed in U.S. PatentApplication Publication No. 2010-0249894 to Oba (the “Oba application”),which is incorporated herein by reference. The heart valve disclosed inthe Oba application includes two separate components: a base stent and avalve component that is mounted to the base stent after the base stentis deployed within the native valve. The base stent is radiallyexpandable and serves to anchor the valve to a patient's annulus. Thebase stent of the Oba application is designed to cooperate with aconventional leaflet wireform (e.g., a separate valve component). Forexample, the valve component includes a conventional, non-expandablesurgical valve that is modified to include an expandable coupling stentthat can be partially expanded to engage the base stent. Thus, the valvecomponent disclosed in the Oba application is not collapsible forimplantation through small surgical incisions. Further, because theheart valve disclosed in the Oba application includes two separateframes, construction can be time consuming and costly.

Other heart valves have been designed for minimally invasive surgeryand/or percutaneous delivery methods. For example, U.S. PatentApplication Publication No. 2010-0036484 discloses a balloon-expandabletranscatheter heart valve and U.S. Patent Application Publication No.2010-0049313 discloses a self-expandable transcatheter heart valve. Bothof these heart valves are designed to be collapsed to a small profileand delivered through catheters. U.S. Patent Application Publication No.2007-0213813, U.S. Pat. No. 7,201,772, and U.S. Patent ApplicationPublication No. 2008-0249619 also disclose various heart valves that canbe delivered via a catheter and implanted relatively quickly.

Accordingly, there remains a need for an improved prosthetic heart valvethat facilitates placement through small incisions, facilitates easierimplantation at the treatment site, and provides improved longevity. Inaddition, devices for, and associated methods of, implanting suchimproved prosthetic valves in a body lumen are also needed, especially amore efficient procedure that reduces the duration a patient needsextracorporeal circulation to undergo a cardiac valve replacement.

SUMMARY OF THE INVENTION

Disclosed embodiments of a prosthetic heart valve can be both radiallycollapsible (and therefore suitable for minimally invasive surgicaltechniques) and provide for relatively quick implantation (e.g., withoutsutures or with a reduced number of sutures required for implantation).Disclosed embodiments can also exhibit flexibility in response tophysiologic loading, thereby potentially increasing durability ascompared to, for example, conventional transcatheter heart valves. Thus,disclosed embodiments of prosthetic heart valves can be implanted usingsmall surgical incisions (e.g., via a thoracotomy) and few or no suturesfor anchoring to a patient's valve. Disclosed embodiments can combinethe ability of surgical valves to undergo deflection or flexion duringphysiologic loading with the ability of transcatheter valves to beradially compressed for minimally invasive delivery methods. These andother advantages of the disclosed embodiments can result in quickerhealing, less scarring, and reduced procedure times in some instances,as well as increased durability of the valve due at least partially tothe valve's flexibility under physiologic loading.

For example, one specific embodiment comprises a prosthetic heart valveframe that is radially expandable from a compressed configuration to anexpanded configuration. The prosthetic valve frame can comprise a stentportion adapted to anchor against a heart valve annulus, the stentportion defining a lumen therethrough, and a wireform portion adapted tosupport at least one valve leaflet. In some embodiments, when theprosthetic valve frame is in the compressed configuration, at least aportion of the wireform portion is positioned within the lumen definedby the stent portion and wherein at least a part of the wireform portionis configured to undergo flexion during pulsatile-loading.

In some embodiments, the wireform portion can comprise a plurality ofcusps (e.g., three cusps) each configured to engage with a respectivevalve leaflet. Each of the cusps can comprise a thinned portionconfigured to facilitate compression of the wireform portion. Forexample, each of thinned portions of the cusps can provide a point ofleast resistance to bending, thereby facilitating collapse orcompression of the valve as a whole, and specifically of the wireformportion.

In some embodiments, at least a portion of the cusps can be positionedinside the lumen of the stent portion when the frame is in itscompressed configuration. The cusps can be spaced apart from the stentportion along a longitudinal direction defined by the lumen of the stentportion in the expanded configuration. For example, as the prostheticvalve frame is transformed from the compressed configuration to theexpanded configuration, at least a portion of the cusps can move frombeing positioned at least partially inside the lumen of the stentportion to a position longitudinally spaced from the stent portion(e.g., outside of the lumen of the stent portion). In some embodiments,the stent portion comprises a plurality of upright struts spaced aroundthe circumference of the stent portion. The upright struts can extend toan outflow end of the wireform portion and can be configured to couplethe wireform portion to the stent portion.

Adjacent cusps can be coupled to one another at each of the uprightstruts so as to form a commissure support at each upright strut. Someembodiments of a prosthetic valve can comprise a plurality of leafletseach having two opposing tabs, the tabs of adjacent leaflets beingconfigured to be coupled together at a respective commissure support.For example, at least a portion of each of the leaflet tabs can bewrapped around at least a portion of an upright strut. In someembodiments, the upright struts can extend to a T-shaped terminationpositioned along a respective commissure support.

At least a part of the wireform portion can be configured to undergoflexion during pulsatile loading (e.g., when implanted in a patient'snative valve annulus). For example, the upright struts and/or thecommissure supports can be configured to flex radially inward and/orradially outward in response to blood flow through the prosthetic valveafter implantation. In some embodiments, an inflow end of the stentportion can be flared outward in the expanded configuration, the inflowend being opposite the wireform portion.

The stent portion of some embodiments can comprise a circumferentialstrut adjacent the wireform portion. Additionally or alternatively, thestent portion can comprise a plurality of vertical struts extending froman inflow end of the stent portion toward the wireform portion. In someembodiments, the vertical struts can be spaced apart from one another,positioned between adjacent upright struts, and can terminate at thecircumferential strut, if present. Disclosed embodiments can comprise aflexible skirt (e.g., a fabric skirt, such as a polyester skirt) coupledto the stent portion and configured to prevent leakage through the stentportion. A skirt can be positioned on the inside and/or outside of thestent portion lumen (e.g., one or more flexible skirts can be coupled tothe inner surface of the stent portion and/or to the outer surface ofthe stent portion). Additionally or alternatively, the prosthetic valvecan include a sealing ring coupled to the wireform portion, the sealingring being configured to be positioned supraannularly.

In another embodiment, a radially collapsible and expandable prostheticheart valve can comprise a frame configured to anchor the prostheticheart valve to a patient's native valve, a leaflet-supporting structurecomprising a plurality of leaflet-supporting cusps and a plurality ofcommissure posts, the commissure posts being positioned between adjacentleaflet-supporting cusps, wherein the commissure posts are configured toundergo cantilevered motion under physiologic loading, and a pluralityof connecting segments spaced apart from one another, each connectingsegment extending from a first end of the stent portion adjacent theleaflet-supporting structure to a leaflet-supporting cusp.

The frame and the leaflet-supporting structure can be undetachablycoupled to one another to form a one-piece prosthetic heart valve. Theleaflet-supporting structure can comprise a cloth covering surroundingthe leaflet-supporting cusps and the commissure posts. The prostheticheart valve can also be provided with a plurality of leaflets, eachleaflet being coupled to a respective leaflet-supporting cusp bysuturing to the cloth covering. The leaflets can be configured such thata central hole through the leaflets remains open when the prostheticheart valve is at rest. The radially collapsible and expandableprosthetic heart valve can also include a sealing ring coupled to theleaflet-supporting structure, the sealing ring being configured to bepositioned supraannularly.

Other embodiments of a prosthetic heart valve that is radiallyexpandable from compressed configuration to an expanded configurationcan comprise a plastically expandable (e.g., balloon-expandable) stentportion configured to anchor the prosthetic valve against a heart valveannulus and a self-expandable wireform portion that is separate from thestent portion. The stent portion can define a lumen therethrough, andthe stent portion can be radially expandable from a collapsed state toan expanded state. In some embodiments, the stent portion can be apre-crimped stent portion that is expandable from a pre-crimped state toan inflated state. In some embodiments, the wireform portion and thestent portion are coupled together only by one or more non-metalliccomponents or devices. In one example, both the wireform portion and thestent portion can be coupled to a cloth-covered leaflet support stent,which effectively couples the wireform portion to the stent portion.

The self-expandable wireform portion can comprise at least onecommissure support and at least one cusp adapted to support at least onevalve leaflet, and the wireform portion can be radially expandable froma constrained configuration to a stress-free configuration. In someembodiments, the stiffness of the stent portion in its collapsed stateis sufficient to prevent the wireform portion from expanding to itsstress-free configuration. In some embodiments, the stent portioncomprises stainless steel, cobalt chromium, or alloys or combinationsthereof, and the wireform portion comprises Nitinol, NiTiCr, NiTiCo, oralloys or combinations thereof.

Some embodiments of a prosthetic heart valve can include a flexibleleaflet support stent coupled to the wireform portion, and/or a sealingring coupled to the flexible leaflet support stent and to the stentportion, wherein the sealing ring is configured to be positionedsupraannularly.

In some embodiments, at least one valve leaflet can be at leastpartially wrapped around a respective post of a flexible leaflet supportstent and the sealing ring can be sutured to a plurality of circularopenings on the stent portion. In some embodiments, the leaflets caneach have two opposing tabs, where the tabs of adjacent leaflets areconfigured to be coupled together at a respective commissure support.For example, at least a portion of each of the leaflet tabs can bewrapped around a post of a flexible leaflet support stent. In someembodiments, the wireform portion comprises three cusps configured toengage with a respective valve leaflet, and each of the cusps comprisesa thinned portion configured to facilitate compression of the wireformportion.

Methods of making and using a prosthetic heart valve are also disclosed.For example, one method of implanting a prosthetic heart valve comprisesradially compressing a prosthetic heart valve to a compressedconfiguration, wherein the prosthetic heart valve comprises a stentportion configured to anchor the prosthetic heart valve to a patient'snative valve and a leaflet-supporting structure, delivering thecompressed prosthetic heart valve to or near a patient's native valveannulus, positioning the leaflet-supporting structure of the prostheticheart valve supraannularly to a patient's aortic valve, and expandingthe prosthetic heart valve to an expanded configuration, wherein thediameter of the prosthetic heart valve in the expanded configuration isgreater than the diameter of the prosthetic heart valve in thecompressed configuration, and wherein in the compressed configuration atleast a portion of the leaflet-supporting structure is positioned withina lumen of the stent portion, and in the expanded configuration theleaflet-supporting structure is positioned externally to the lumen ofthe stent portion.

In some methods, the prosthetic heart valve includes a one-pieceprosthetic heart valve frame. In some methods, delivering the prostheticheart valve can comprise delivering the prosthetic heart valvetransapically. In some methods, expanding the prosthetic heart valve caneffectively anchor the prosthetic heart valve without suturing the valveto the native valve.

In other methods, a pre-crimped balloon expandable stent portion can beprovided and configured to anchor the prosthetic heart valve to apatient's native valve. The pre-crimped stent portion can be coupled toa self-expanding wireform portion and a plurality of leaflets to formthe prosthetic heart valve, and the stent portion and the wireformportion can be coupled to one another via a cloth-covered flexibleleaflet support stent. In some methods, the diameter of the stentportion in an expanded configuration is greater than the diameter of thestent portion in a compressed configuration, and expansion of the stentportion can enable self-expansion of the wireform portion.

The foregoing and other objects, features, and advantages of theinvention will become more apparent from the following detaileddescription, which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained and other advantages and featureswill appear with reference to the accompanying schematic drawingswherein:

FIG. 1 illustrates an anatomic anterior view of a human heart, withportions broken away and in section to view the interior heart chambersand adjacent structures.

FIG. 2 illustrates an anatomic superior view of a section of the humanheart showing the tricuspid valve in the right atrium, the mitral valvein the left atrium, and the aortic valve in between, with the tricuspidand mitral valves open and the aortic and pulmonary valves closed duringventricular diastole (ventricular filling) of the cardiac cycle.

FIG. 3 shows an anatomic superior view of a section of the human heartshown in FIG. 2, with the tricuspid and mitral valves closed and theaortic and pulmonary valves open during ventricular systole (ventricularemptying) of the cardiac cycle.

FIG. 4 shows an anatomic anterior perspective view of the left and rightatria, with portions broken away and in section to show the interior ofthe heart chambers and associated structures, such as the fossa ovalis,coronary sinus and the great cardiac vein.

FIG. 5 shows a perspective view of one embodiment of a one pieceprosthetic heart valve frame with leaflets partially secured to theframe.

FIG. 6 shows a cutaway view of a human heart with a prosthetic heartvalve implanted within the native valve annulus

FIG. 7 shows an elevation view of one embodiment of a one pieceprosthetic heart valve frame in an expanded configuration.

FIG. 8 shows a perspective view of the prosthetic heart valve frame ofFIG. 7

FIG. 9 shows a close-up of a portion of the prosthetic heart valve frameof FIG. 7.

FIG. 10 is a perspective view of the prosthetic heart valve frame ofFIGS. 7-8 in a collapsed configuration.

FIG. 11 is an elevation view of another embodiment of a one pieceprosthetic heart valve frame in an expanded configuration.

FIG. 12 is a top plan view of the prosthetic valve frame of FIG. 11 inan expanded configuration.

FIG. 13 is a top plan view of the collapsed prosthetic heart valve frameof FIGS. 11-12.

FIG. 14 shows an elevation view of the prosthetic heart valve frame ofFIGS. 11-13 in a collapsed configuration.

FIG. 15 is a section view of one method of leaflet attachment, takenalong line 12-12 in FIG. 11.

FIG. 16 is a section view of an alternative method of leafletattachment.

FIG. 17 is an elevation view of another embodiment of a one pieceprosthetic heart valve frame.

FIG. 18 is an elevation view of another embodiment of a one pieceprosthetic heart valve frame.

FIG. 19 shows a perspective view of one embodiment of a two pieceprosthetic heart valve with leaflets partially secured.

FIG. 20 shows a cutaway view of a human heart with a prosthetic heartvalve implanted within the native valve annulus.

FIG. 21 shows an elevation view of one embodiment of a two pieceprosthetic heart valve frame in an expanded configuration.

FIG. 22 shows a close-up of a portion of the prosthetic heart valveframe of FIG. 21.

FIG. 23 is a perspective view of the prosthetic heart valve frame ofFIG. 21 in a collapsed configuration.

FIG. 24 is a top plan view of the collapsed prosthetic heart valve frameof FIG. 23 as compared to the expanded prosthetic heart valve frame ofFIG. 21.

FIG. 25 shows another embodiment of a collapsed configuration of theheart valve frame of FIG. 21.

FIG. 26 shows an elevation view of the prosthetic heart valve frame ofFIG. 21 in a collapsed configuration for delivery.

FIG. 27 shows a top plan view of the configuration shown in FIG. 26.

FIG. 28 shows a perspective view of one embodiment of a leaflet supportstent for use with the disclosed prosthetic heart valve frame.

FIG. 29 shows a perspective view of the leaflet support stent of FIG.28, in a collapsed configuration

FIG. 30 shows a perspective view of one embodiment of a flexible sealingring, without any cloth covering.

FIG. 31 shows a perspective view of one embodiment of a subassembly,which includes the leaflet support stent of FIGS. 28-29 and the sealingring of FIG. 30, covered in cloth and coupled together.

FIG. 32 shows a perspective view of one embodiment of a wireform portionin the process of being covered with cloth.

FIG. 33 shows a perspective view of one embodiment of a wireform portioncovered in cloth.

FIG. 34 shows a perspective view of placement of leaflets within thecloth covered wireform portion of FIG. 33.

FIG. 35 shows a perspective view of the cloth covered wireform portionand leaflets of FIG. 34 in combination with the subassembly shown inFIG. 31.

FIG. 36 shows one embodiment of a two piece prosthetic heart valve framein a collapsed configuration positioned for delivery on an inflatabledevice.

FIG. 37 shows the prosthetic heart valve frame of FIG. 36, as theinflatable device begins to be inflated.

FIG. 38 shows the prosthetic heart valve frame of FIGS. 36-37 afterfurther inflation of the inflatable device, showing full expansion ofthe stent portion.

FIG. 39 shows the prosthetic heart valve frame of FIGS. 36-38 after fullexpansion of the wireform portion and the stent portion.

FIG. 40 shows a perspective view of another embodiment of a leafletsupport stent for use with the disclosed prosthetic heart valve frame.

FIG. 41 shows a side elevation view of the leaflet support stent shownin FIG. 40, combined with a sealing ring and having a cloth coveringsurrounding it.

FIG. 42 shows a top plan view of the cloth-covered leaflet support stentof FIG. 41, in a radially compressed configuration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As used in this application and in the claims, the singular forms “a,”“an,” and “the” include the plural forms unless the context clearlydictates otherwise. Additionally, the term “includes” means “comprises.”Although the operations of exemplary embodiments of the disclosed methodmay be described in a particular, sequential order for convenientpresentation, it should be understood that the disclosed embodiments canencompass an order of operations other than the particular, sequentialorder disclosed. For example, operations described sequentially may insome cases be rearranged or performed concurrently. Further,descriptions and disclosures provided in association with one particularembodiment are not limited to that embodiment, and may be applied to anyembodiment disclosed herein. Moreover, for the sake of simplicity, theattached figures may not show the various ways in which the disclosedsystem, method, and apparatus can be used in combination with othersystems, methods, and apparatuses.

As used herein, “self expand” means to elastically recover from acollapsed (e.g., a compressed) configuration when an external restraint(e.g., a suture, a sheath, or a holder) is removed. A component alsoself-expands if it expands upon exposure to a threshold temperatureinside the body. Additionally, a component self-expands if itelastically recovers from a collapsed state in response to expansion ofanother component. For example, as will be described below, in someembodiments, the wireform portion can self-expand after balloonexpansion of the stent portion, where the stent portion is stiff enoughto hold the wireform portion in its collapsed state, preventingself-expansion of the wireform portion while the stent portion is in itscompressed configuration.

As used herein, “balloon expandable” means to plastically expand from acollapsed state with the use of an inflatable or expandable device, suchas an inflatable balloon positioned on a delivery catheter.

As used herein, “at rest” means a configuration of a valve and/or aframe when the respective valve and/or frame is still and free fromexternally applied loads (e.g., pressure gradients through the valve,forces applied by retaining and/or delivery devices to retain the valvein a collapsed configuration).

As used herein, a structure is “undetachably coupled” to anotherstructure if the structures cannot be separated from one another withoutdestroying or otherwise rendering inoperable the device (e.g., thestructures cannot be separated from one another without cutting throughmetal).

As used herein, the term “wireform” refers generally to a portion of aprosthetic heart valve that supports the leaflets. A wireform may or maynot be formed from one or more pieces of wire. A wireform includes athree-dimensional body formed of one or more wires or similarly-shapedelongate members. A wireform as used herein can also be cut or otherwiseformed from tubing or a sheet of material. In some embodiments, each ofthe one or more members has a substantially constant cross-sectionalshape along its length. In some embodiments, one or more of the elongatemembers forming the wireform can have portions of varyingcross-sectional shape or thickness along its length. By way of example,elongate members can have a substantially solid, rectangular or squarecross-sectional shape. Other cross-sectional shapes (e.g., circular,annular, hollow rectangle) are also possible.

Overview

Disclosed embodiments of a prosthetic heart valve can advantageouslyprovide a heart valve that allows for flexion (e.g., slight movement)during in vivo pulsatile loading as well as the capability to beradially compressed or collapsed for delivery, such as delivery viaminimally invasive surgical techniques, and expanded. While thedescribed embodiments relate to heart valve prostheses, disclosedconcepts can also be applied to other types of valves as well.

Generally, disclosed embodiments of prosthetic heart valve frames can becategorized as being one-piece frames or two-piece frames. FIGS. 5-18illustrate prosthetic valves and valve components utilizing one-pieceframes. FIGS. 19-42 illustrate prosthetic valves and valve componentsutilizing two-piece frames. For convenience and clarity, the one-piecevalve frames will be discussed first, followed by the two-piece valveframes, but this organization does not in any way limit the scope ofdisclosed prosthetic heart valves. Variations and components discussedwith respect to one frame type can also be applied to the other frametype in some embodiments, and the disclosure should not be read to beotherwise limiting.

Overview of Prosthetic Valve Having a One-Piece Valve Frame

FIG. 5 shows a prosthetic heart valve 500, which generally includes astent portion 502 and a wireform portion 504. The stent portion 502 canbe formed of a plurality of vertical and horizontally-extending struts522, 524, and the wireform portion 504 can include leaflet-supportingcusps 514 and commissure supports 516. Upright struts 508 (also referredto as commissure posts) can undetachably couple the stent portion 502 tothe wireform portion 504. The prosthetic valve 500, which is shown in anexpanded configuration in FIG. 5, can also include a plurality ofleaflets 528, a flexible skirt 538 (shown partially broken away), asealing ring 546 (shown partially broken away), and a cloth covering 530(shown partially broken away) over the wireform portion 504, each ofwhich will be described in further detail below.

FIG. 6 shows the prosthetic heart valve 500 implanted within a patient'snative valve annulus 548 (e.g., aortic valve annulus 548). As shown, theprosthetic valve 500 can be implanted such that at least a portion ofthe valve 500 is positioned supraannularly. For example, the wireformportion 504 can be positioned supraannularly, while the stent portion502 is configured to anchor the prosthetic valve 500 in place within thenative valve annulus 548. The stent portion 502 can be slightly flaredoutward at the inflow end 510, such that the stent portion 502frictionally engages the native valve annulus 548 to prevent migrationof the prosthetic valve 500. Additionally or alternatively, an optionalsealing ring 546 can be provided adjacent the wireform portion 504. Saidsealing ring can be configured to engage the shelf 552 of the nativevalve annulus 548 so as to prevent migration of the prosthetic valve 500into the ventricle 550. The sealing ring 546 can also create a sealaround the prosthetic valve 500 such that substantially no blood canpass between the native valve annulus 548 and the prosthetic valve 500.

Thus, disclosed embodiments can be positioned supraannularly to apatient's native valve (e.g., the stent portion can be positioned atleast partially within the annulus and at least part of the wireformportion can be positioned supraannularly). In this position, aprosthetic valve may experience significant pressure during diastole,which can push the prosthetic valve down towards the ventricle. Thecusps of the wireform portion can be configured to engage with theannulus, creating a shelf to resist such pressure (e.g., the cusps ofthe wireform portion can have a greater diameter than the nativeannulus). Additionally or alternatively, the optional flexible sealingring can be configured to rest on the native annulus when the prostheticheart valve is deployed in place at the target site. For example, thesealing ring can have a greater diameter than the native annulus and canthereby further resist movement or dislodgement of the valve towards theventricle.

Components of the prosthetic valve 500 will now be described in greaterdetail.

Leaflets

Returning to FIG. 5, the wireform portion 504 can comprise a pluralityof cusps 514 configured to engage with a respective valve leaflet 528.For example, prosthetic valve 500 includes three cusps 514, each of thecusps 514 being configured to engage with one of three leaflets 528secured to prosthetic valve 500. For example, leaflets can be secured tothe cusps 514 in a manner similar to conventional surgical valves, withthe leaflets being sutured to the cloth covering 530 surrounding thecusps 514. In this manner, the leaflets 528 can open when exposed to apositive pressure gradient in a fluid (e.g., blood) passing between theinflow end 510 and the outflow end 512 and close (or coapt) when exposedto a negative pressure gradient between the inflow end 510 and theoutflow end 512. When the leaflets 528 are closed, as shown in FIG. 5,they can be configured to retain a central hole 554 through the centerof the leaflets 528 when the valve 500 is at rest (e.g., not subject toany pressure gradient). When the leaflets 528 are subjected to apressure gradient (e.g., after implantation in a patient's native valveannulus) the leaflets can be configured to close completely such thatsubstantially no blood leaks through the closed leaflets duringdiastole. Conventional prosthetic valves configured to be radiallycompressed for delivery disadvantageously must be configured such thatthe leaflets close completely when the valve is at rest.

For illustration purposes, the leaflets 528 are shown with coupling tothe prosthetic valve 500 still in progress. The leaflets 528 can eachinclude tabs 532 at opposing ends of the leaflets. The tabs 532 canfacilitate coupling of the leaflets 528 to the wireform portion 504. Forexample, as will be explained in further detail below in connection withFIGS. 15-16, each tab 532 can extend between an upright strut 508 and anextension of one of the leaflet-supporting cusps 514 adjacent theoutflow end 512 (e.g., adjacent the commissure support 516). Adjacenttabs 532 can be at least partially wrapped around the respective uprightstrut 508 and coupled together (e.g., with sutures 534) around theupright strut 508. In FIG. 5, only one of the three sets of leaflet tabs532 has been sutured together around an upright strut 508. The leafletscan additionally be secured to the frame such as by being sutured to thecloth covering 530 surrounding the cusps 514.

Examples of suitable materials for forming the valve leaflets includepericardial tissue (e.g., bovine, porcine, or cadaver pericardialtissue), biocompatible synthetic polymers, and any other suitablenatural or synthetic material. While three leaflets are shown, variousembodiments can comprise one, two, three, or more leaflets.

Flexible Skirt

In addition to leaflets, the prosthetic valve 500 can include a flexibleskirt 538. The flexible skirt 538 can be, for example, a polyesterfabric (e.g., Dacron) skirt. The flexible skirt 538 is shown coupled tothe inner surface of the stent portion 502 (e.g., positioned within alumen 506 of the stent portion 502) and can be configured to preventleakage through the stent portion 502 once the prosthetic valve 500 isimplanted within a patient's native valve. In the specific embodimentshown, the flexible skirt 538 can be coupled to one or more of thevertical struts 522, such as to circular portions 540 adjacent thecircumferential strut 520 (e.g., with sutures 542). In otherembodiments, skirt 538 can be coupled to the stent portion 502 inadditional places and/or in alternative arrangements.

While FIG. 5 shows the skirt 538 positioned within the lumen 506 of theprosthetic valve 500, in some embodiments, skirt 538 can be positionedon the outer surface of the stent portion (e.g., outside of the lumen506). In some embodiments, the prosthetic valve 500 can include a skirton both the inside and outside surfaces of the stent portion 502. Inalternative embodiments, the prosthetic valve can be provided without aflexible skirt 538.

While FIG. 5 shows only a cut-away view of the skirt 538, the skirt 538can extend around the entire circumference of the stent portion 502.Additionally, as shown, the skirt 538 can be essentially the same heightas the stent portion 502. For example, the skirt 538 can extendsubstantially from an inflow end 510 and towards an outflow end 512,terminating, in some embodiments, at cusp portions 514, oralternatively, adjacent a circumferential strut 520 positioned near thewireform portion 504. Thus, the skirt 538 can substantially cover theentire stent portion 502 and optionally the area of the wireform portionbelow the cusp portions 514. In alternative embodiments, the skirt 538can be configured to only cover a portion of the stent portion 502.

Cloth Covering

The cloth covering 530 can be secured to the wireform portion 504 suchthat opposing longitudinal edges of the cloth 530 are brought togetherto form a seam external to the wireform portion 504 (see seam 1150 inFIG. 11). The seam can be formed such as by suturing, adhesion, and/orother well-known cloth-edge joining techniques. The cloth covering 530can function to provide a substrate for suturing the leaflets to. Forexample, the cloth covering 530 can be sutured around the wireformportion 504 and the leaflets subsequently can be sutured to the cloth530 along the contour of the leaflet-supporting cusps 514 (e.g., on theoutside of the leaflet-supporting cusps 514). The cloth 530 can alsoprevent the leaflets from contacting the metal of the leaflet-supportingcusps 514 and commissure supports 516, thereby potentially decreasingwear on the leaflets. Cloth covering 530 can comprise any suitablebiocompatible material, such as polyester or polyethylene terephthalate.

In some embodiments, the flexible skirt 538 can extend up to meet thecloth covering 530 on the wireform portion 504 so that there is no gapbetween them. The flexible skirt 538 can be coupled to the clothcovering 530 so as to not impede movement of the leaflets 528 or cusps514. For example, as will be described in further detail below, as theprosthetic valve 500 is compressed for delivery, in some embodiments thecusps 514 move from their position in the expanded configuration to aposition inside the lumen 506. The flexible skirt 538 can be coupled tothe stent portion 502, the circumferential strut 520, and/or the clothcovering 530 on the wireform portion 504 so as not to impede suchmovement of the cusps 514. In some embodiments, the flexible skirt 538can follow the contour of the commissure supports 516 such thateverything below the leaflets 528 is substantially sealed off.

Sealing Ring

The prosthetic heart valve 500 can include a flexible sewing ring orsealing ring structure, such as a tri-lobular sealing ring. The sealingring can be arranged such that sinus-shaped portions of the ring can bealigned with the cusps of the wireform portion. The sealing ring canform a tight seal between the wireform portion and the stent portion ofdisclosed prosthetic heart valve frames, can form a tight seal betweenthe prosthetic valve and native valve annulus, and/or can provide asuture point for securing the prosthetic valve frame to the native valveannulus (in addition to or instead of using the flared stent portion toanchor the valve frame). For example, a flexible sealing ring 546 can becoupled to the wireform portion 504 in some embodiments and can be usedto attach nadir sutures to the patient's annulus. In other embodiments,the sealing ring 546 can be provided without suturing it to the nativevalve tissue. The sealing ring 546 can additionally or alternatively beconfigured to provide a seal positioned between the wireform portion 504and the stent portion 502 of the prosthetic heart valve frame, the sealbeing configured to enhance the effectiveness of or replace the flexibleskirt discussed above.

The sealing ring 546 can be sewn to the wireform cloth 530 through theleaflets in some embodiments. In some embodiments, the leaflets can besandwiched between the wireform cloth 530 and the sealing ring 546,which may or may not include a cloth covering itself. FIG. 5 shows thatthe sealing ring 546 can be positioned on the wireform portion 504adjacent the stent portion 502.

Frame Structure

Embodiments of a frame for use with a prosthetic heart valve will now bedescribed. FIGS. 7-8 illustrate the frame 501 of the prosthetic heartvalve 500 of FIG. 5, with the frame still in its expanded configuration.The frame 501 is shown without a plurality of leaflets, a cloth coveringover a portion of the frame, a sealing ring, or a fabric or flexibleskirt of another material, in order to provide a clear view of theframe.

Frame 501 can comprise a stent portion 502 and a wireform portion 504(wireform portion 504 is also referred to as a leaflet support portion).Generally, stent portion 502 can be configured to anchor the frame 501to a patient's native valve annulus and wireform portion 504 can beconfigured to receive and support at least one valve leaflet. Forexample, once the prosthetic valve 500 is positioned at an implantationsite, the stent portion 502 can engage an inner periphery of a bodylumen (e.g., a native annulus) at the implantation site. Disclosedembodiments can engage with the native annulus via the stent portion 502and/or a sealing ring, such as by engaging the aortic annulus, thefibrous annulus, and/or the aorta wall (e.g., a position downstream fromthe location of the native leaflets)

The stent portion 502 can define a lumen 506 therethrough. The stentportion 502 can comprise any suitable combination of struts and wiresthat can allow the stent portion to radially collapse to a compressedconfiguration for delivery, and that can also facilitate anchoring ofthe frame 501 within a patient's native valve.

The specific embodiment shown in FIGS. 7-8 includes a plurality ofupright struts 508 spaced around the circumference of the stent portion502. The upright struts 508 can extend substantially from an inflow end510 to an outflow end 512 of the frame 501. As shown in FIGS. 7-8, theinflow end 510 corresponds to the end 510 of the stent portion 502opposite the wireform portion 504. In alternative embodiments, theupright struts may extend only partially towards the inflow end 510and/or only partially towards the outflow end 512. The upright struts508 can be configured to couple the stent portion 502 to the wireformportion 504. For example, the upright struts can undetachably couple thestent portion 502 and the wireform portion 504 so that the frame 501 isa one-piece frame 501.

In some specific embodiments, each of the cusps 514 can include athinned portion 515 (best seen in FIG. 7) configured to facilitatecompression of the wireform portion 504. The upright struts 508 can, insome embodiments, carry at least a portion of the load due to pulsatileloading, and can therefore at least partially reduce the load on thecusps 514. Thus, the upright struts 508 can at least partiallycompensate for any reduction in strength of the cusps 514 due to thethinned portion 515.

The one or more thinned portions 515 can be configured to provide thecusps 514 with greater flexibility, especially near the thinned portions515. For example, the thinned portion 515 can be configured to deformmore readily than the adjacent, thicker, areas of the cusps 514. In someembodiments, the thinned portions 515 can be positioned substantiallynear the center of each cusp, but other configurations are alsosuitable. For example, each cusp 514 could include at least two thinnedportions 515 spaced apart from each other along the cusp 514. Thethinned portions 515 can, for example, serve as a hinge and facilitatebending of the cusps 514 during transformation of the wireform portion504 (and the frame 501 as a whole) from the expanded configuration shownin FIGS. 7-8 to a compressed configuration

As shown in FIG. 7, in an expanded configuration, the cusps 514 can bespaced apart from the stent portion 502 along a longitudinal directiondefined by the lumen 506 of the stent portion 502. For example, thecusps 514 can be spaced apart from the stent portion 502 along thelongitudinal axis Z in the shown expanded configuration. Additionally oralternatively, the cusps 514 can be positioned further outward radiallythan the stent portion 502 when in the expanded configuration. Forexample, the cusps 514 can have a greater diameter in the expandedconfiguration than the circumferential strut 520. In this configuration,the cusps 514 can engage the native valve annulus (e.g., the shelf 552of annulus 548 seen in FIG. 6).

Adjacent cusps 514 can be coupled to one another at each of the uprightstruts 508 so as to form a commissure support 516 at each upright strut508 adjacent the outflow end 512. For example, with reference to FIG. 8,adjacent cusps 514 a and 514 b can be coupled to one another at uprightstrut 508 a to form a commissure support 516 a. Similarly, adjacentcusps 514 a and 514 c can be coupled to one another at upright strut 508b to form commissure support 516 b, and adjacent cusps 514 b and 514 ccan be coupled to one another at upright strut 508 c to form commissuresupport 516 c.

The commissure supports 516 can lean slightly outward relative to thelumen 506 (e.g., the central flow axis Z of the prosthetic valve frame501) when the valve is at rest. The commissure supports 516 canalternatively be oriented to lean inwardly at a slight angle relative tothe longitudinal axis Z. Alternatively, the commissure supports 516 canbe substantially vertical (e.g., substantially parallel to the centralflow axis) when the valve is at rest, as shown in FIG. 7.

At least part of the wireform portion 504 can be configured to undergoflexion (e.g., can be configured to move slightly) during normalphysiologic loading when implanted in a patient's native valve. Forexample, the upright struts 508 and commissure supports 516 (e.g., thefree end of the commissure supports 516 adjacent the outflow end 512)can be configured to flex in the direction indicated by arrows 518(e.g., radially inward) during each cardiac cycle, and likewise can beconfigured to move radially outward, returning to their originalpositions later in each cardiac cycle.

The prosthetic valve frame 501 can be positioned at the implantationsite such that the cantilevered commissure supports 516 can deflectindependently of the surrounding body lumen to which the valve frame 501is secured. The ability of the commissure supports 516 to flex in thismanner can allow the leaflets supported by the commissure supports 516and cusps 514 to close more gently, thereby relieving stress on theleaflets during diastole.

In some embodiments, the wireform portion 504 and/or the upright struts508 can be thinner than would normally be expected, in order to optimizethe movement (e.g., flexion) during pulsatile in vivo loading. Suchflexion can contribute to the longevity and durability of disclosedprosthetic heart valve frames 500. The stiffness of the upright struts508 and/or the wireform portion 504 can be optimized such that thecommissure supports 516 deflect under physiologic loading.

In some embodiments, the upright struts 508 and/or commissure supports516 can be configured to deflect an amount similar to that ofconventional surgical valves and an amount greater than that ofconventional transcatheter valves. For example, while a conventionaltranscatheter valve may only flex tens of microns or less, the presentlydisclosed valve frames can flex up to around 1 mm or more, with flexionvarying slightly with different sized valve frames. Thus, the presentlydisclosed prosthetic heart valve frames can flex about 10-100 times morethan conventional transcatheter valves.

For example, FIG. 9 shows the deflection of a commissure support 516under physiologic loading. The commissure support 516 and upright struts508 can move in a cantilevered fashion radially inward and outwardduring each cardiac cycle. As shown in FIG. 9, the commissure support516 can deflect radially inward a distance a. In some embodiments, a canbe about 1 mm or greater.

Such flexion can be adjusted and optimized to improve hemodynamicsthrough the valve. For example, as a result of this greater flexion, theleaflets can advantageously be arranged to retain a central hole (e.g.,the three-pointed star-shaped hole 554 seen in FIG. 5 where the leafletsmeet in the center of the valve) when the valve is at rest (i.e., notsubjected to any pressure gradient). Under physiologic loading (andflexion of the commissures), the central hole is closed completely, butthe leaflets generally come together in a controlled, gentle fashion. Onthe other hand, conventional transcatheter valves typically cannot havesuch a central hole in the leaflets—the leaflets must be completelyclosed when the valve is at rest, because the valve is unable to flex.As a result, the leaflets of traditional transcatheter valves tend tocollide together more forcefully, which can disadvantageously reduce thelifespan of the prosthetic valve.

Returning to FIGS. 7-8, the stent portion 502 of the frame 501 can beflared outward in its expanded configuration. For example, the diameterof the lumen 506 at the inflow end 510 of the stent portion 502 can begreater than the diameter of the lumen 506 of the stent portion 502adjacent the wireform portion 504, thereby creating a flared stentportion 502. The flared configuration of the stent portion 502 canfacilitate anchoring of the stent portion 502 within the patient'snative valve annulus without the use of sutures (or with a reducednumber of sutures as compared with conventional prosthetic heartvalves). For example, as shown in FIG. 6, the flared stent portion 502can engage with the valve annulus, keeping the frame 501 in position,with the wireform portion 504 being positioned distal to the annulus.Therefore, in some embodiments, at least part of the wireform portion504 does not contact the native valve annulus once the frame 501 isimplanted. For example, in some embodiments, the cusps 514 and/or asealing ring may contact the native valve annulus, while the commissuresupports 516 do not.

In some embodiments, the leaflet-supporting cusps 514 can protruderadially outward past the stent portion 502 (or at least past the upperend of stent portion 502 adjacent the cusps 514) so as to form an edgeor shelf which can further discourage migration of the prosthetic heartvalve frame 501 during diastole (e.g., the shelf formed by the cusps 514could engage with or rest against the native annulus, thereby workingtogether with the flared stent portion to prevent migration of the valveframe into the ventricle). In other words, the flared lower end of thestent portion 502 can be positioned on one side of the native annulusand can have a diameter larger than the annulus to prevent migration inone direction, while the cusps 514 can be positioned on the oppositeside of the annulus and can have a diameter larger than the annulus toprevent migration in the opposite direction. For example, in embodimentswhere the frame 501 comprises Nitinol or another superelastic material(e.g., shape memory materials), the cusps 514 can be shape set such thatthey are positioned further out radially than at least the upper end ofstent portion 502 in the expanded configuration.

In some embodiments, the frame 501 can include a circumferential strut520. The circumferential strut 520 can be positioned on the stentportion 502 adjacent the wireform portion 504 and can be configured toincrease the radial stiffness of the stent portion 502 and/or increasethe effective stiffness of the upright struts 508. Circumferential strut520 can be configured to be essentially straight (e.g., have anessentially flat side profile) when the frame 501 is in its expandedconfiguration and can be bent or folded with the frame 501 is in itscompressed configuration. The circumferential strut 520 can essentiallyserve as a boundary between the stent portion 502 and the wireformportion 504, although the upright struts 508 continue from one side ofthe circumferential strut 520 to the other.

The stent portion 502 can also include a plurality of vertical struts522 that extend from the inflow end 510 to the circumferential strut520. The vertical struts 522 can be spaced apart from one another and aplurality of vertical struts 522 can be positioned between adjacentupright struts 508. At least one row of horizontally-extending struts524 can be positioned around the circumference of the stent portion,extending between adjacent vertical struts 522 and/or between an uprightstrut 508 and a vertical strut 522. FIGS. 5-8 show three rows ofhorizontally extending struts 524, but more or fewer rows are alsopossible. In the specific embodiment shown, the horizontally-extendingstruts 524 can be substantially U-shaped or V-shaped, with the curvedportion or vertex portion 526 arranged towards the outflow end 512 ofthe frame 501. Bending or extending of the horizontally-extending struts524 can decrease or increase, respectively, the distance betweenadjacent vertical struts 522 or the distance between an adjacentvertical strut 522 and upright strut 508. Thus, thehorizontally-extending struts 524 can facilitate compression of thestent portion 502 and therefore can facilitate compression of theoverall frame 502. Other shapes and configurations of the stent portionare also possible. Generally, any shape or design can be provided as thestent portion of disclosed prosthetic heart valves that allow for radialcompression and expansion of the stent portion.

FIG. 10 shows the valve frame 501 in a collapsed configuration (e.g.,radially compressed for delivery). As shown in FIG. 10, when the valveframe 501 is radially compressed, the circumferential strut 520 canbecome pinched into a V shape between adjacent circular openings 540. Asshown in FIG. 10, in the compressed configuration, at least a portion ofthe wireform portion 504 can be positioned at least partially inside thestent portion 502. For example, at least a portion of the cusps 514 canbe positioned inside (e.g., within) the lumen 506 of stent portion 502in the compressed configuration. This positioning can be accomplishedvia movement of the cusps 514 towards the inflow end 510 as the stentportion 502 is being radially crimped. Thus, the wireform portion 504can be configured to collapse further radially than the stent portion502.

In an alternative embodiment, the wireform portion 504 can be configuredto collapse less in the radial direction that does the stent portion502. For example, at least a portion of the wireform portion 504 can bepositioned at least partially outside the stent portion 502. Forexample, at least a portion of the cusps 514 can be positioned outside(e.g., against the outer surface) of stent portion 502 in the compressedconfiguration. This positioning can be accomplished via movement of thecusps 514 towards the inflow end 510 as the stent portion 502 is beingradially crimped more than the cusps 514 (e.g., the stent portion 502can be radially crimped to a smaller compressed diameter than the cusps514).

FIGS. 11-14 illustrate an additional embodiment of a prosthetic heartvalve frame 1100. FIGS. 11-12 show the valve frame 1100 in an expandedconfiguration and FIGS. 13-14 show the prosthetic heart valve frame 1100in an compressed, or collapsed configuration 1100′. The prosthetic heartvalve frame 1100 is similar to the prosthetic heart valve frame 501 ofFIGS. 5-10 except that valve frame 1100 does not include acircumferential strut 520 on the stent portion. Additionally, theprosthetic valve frame 1100 does not include thinned portions on theleaflet-supporting cusps 1114 (e.g., thinned portions 515 of cusps 514).Either or both of these features can be provided with the embodimentshown in FIGS. 11-14.

Prosthetic valve frame 1100 can comprise a stent portion 1102 and aleaflet structure 1104. Leaflets are not shown in FIGS. 11-14, forclarity. Generally, stent portion 1102 can be configured to anchor theprosthetic valve frame 1100 to a patient's native valve annulus andleaflet structure 1104 can be configured to receive and support at leastone valve leaflet. The prosthetic valve frame 1100 can define a lumen1106 therethrough. The stent portion 1102 can comprise any suitablecombination of struts and/or wires that can allow the stent portion 1102to radially collapse to a compressed configuration for delivery, andthat can also facilitate anchoring of the expanded prosthetic valveframe 1100 within a patient's native valve. The leaflet structure 1104can comprise a plurality of leaflet-supporting cusps 1114 eachconfigured to engage with a respective valve leaflet.

The specific embodiment shown in FIGS. 11-14 includes a plurality ofcommissure posts 1108 spaced around the circumference of the stentportion 1102 and positioned between adjacent leaflet-supporting cusps1114. The commissure posts 1108 can extend substantially from an inflowend 1110 to an outflow end 1112 of the prosthetic valve frame 1100. Asshown in FIGS. 11-14, the inflow end 1110 corresponds to the end 1110 ofthe stent portion 1102 opposite the leaflet structure 1104. Inalternative embodiments, the commissure posts may extend only partiallytowards the inflow end 1110 and/or only partially towards the outflowend 1112. The commissure posts 1108 can be configured to couple thestent portion 1102 to the leaflet structure 1104. For example, thecommissure posts 1108 can undetachably connect the stent portion 1102and the leaflet structure 1104 so that the prosthetic valve frame 1100is a one-piece prosthetic valve frame 1100.

As shown in FIGS. 13-14, in a compressed configuration, at least aportion of the leaflet structure 1104 can be positioned at leastpartially inside the frame 1102. For example, at least a portion of theleaflet-supporting cusps 1114 can be positioned inside (e.g., within)the lumen 1106 of frame 1102 in the compressed configuration. Thispositioning can be accomplished via movement of the cusps 1114 towardsthe inflow end 1110 as the frame 1102 is being radially crimped. Thus,the leaflet structure 1104 can be configured to collapse furtherradially than the frame 1102.

Alternatively, the leaflet structure 1104 can be configured to collapseless in the radial direction that does the frame 1102. For example, atleast a portion of the leaflet structure 1104 can be positioned at leastpartially outside the frame 1102. For example, at least a portion of thecusps 1114 can be positioned outside (e.g., against the outer surface)of frame 1102 in the compressed configuration. This positioning can beaccomplished via movement of the cusps 1114 towards the inflow end 1110as the frame 1102 is being radially crimped more than the cusps 1114(e.g., the frame 1102 can be radially crimped to a smaller compresseddiameter than the cusps 1114).

At least part of the leaflet structure 1104 can be configured to undergoflexion (e.g., can be configured to move slightly) during normalphysiologic loading when expanded and implanted in a patient's nativevalve. For example, the commissure posts 1108 and commissure supports1116 can be configured to flex radially inward during each cardiaccycle, and likewise can be configured to flex radially outward to theiroriginal positions later in each cardiac cycle. Such flexion cancontribute to the longevity and durability of disclosed prosthetic heartvalves 1100.

FIGS. 11-12 show the valve frame 1100 in an expanded configuration 1100.The stent portion 1102 of the prosthetic valve frame 1100 can be flaredoutward in its expanded configuration, as shown in FIGS. 11-12. Forexample, the diameter of the lumen 1106 at the inflow end 1110 of thestent portion 1102 can be greater than the diameter of the lumen 1106 ofthe stent portion 1102 adjacent the leaflet structure 1104, therebycreating a flared stent portion 1102.

FIG. 12 shows the valve frame 1100′ in its compressed configurationinside the expanded valve frame 1100 for reference. In some embodiments,disclosed prosthetic heart valves can be compressed or crimped to about60% of its expanded size (e.g., the diameter of the valve in itscompressed configuration can be about 60% of the diameter in theexpanded configuration). In one specific embodiment, a 25 mm frame canbe crimped to have an outer diameter of around 15 mm or less fordelivery of the valve. Other sizes of prosthetic heart valves can becompressed similar amounts. For example, a size 19 mm valve can becompressed to about 11.5 mm or less, a 21 mm valve can be compressed toabout 12.75 mm or less, a 23 mm valve can be compressed to about 14 mmor less, a size 27 mm valve can be compressed to about 16.25 mm or less,and a size 29 mm valve can be compressed to about 17.5 mm or less. Insome embodiments, the prosthetic heart valve can be compressed to aneven smaller diameter relative to the expanded diameter (e.g., less than60% of the expanded diameter).

As seen in FIGS. 11-14, the stent portion 1102 can include a pluralityof vertical struts 1122 that extend from the inflow end 1110 towards theoutflow end 1112. The vertical struts 1122 can be spaced apart from oneanother and positioned between adjacent commissure posts 1108. At leastone row of horizontally-extending struts 1124 can be positioned aroundthe circumference of the stent portion 1102, extending between adjacentvertical struts 1122 and/or between a commissure post 1108 and avertical strut 1122. FIGS. 11-12 and 14 show three rows of horizontallyextending struts 1124, but more or fewer rows are also possible. In thespecific embodiment shown, the horizontally-extending struts 1124 can besubstantially U-shaped or V-shaped, with the curved portion or vertexportion 1126 arranged towards the outflow end 1112 of the prostheticvalve frame 1100. Bending or extending of the horizontally-extendingstruts 1124 can decrease or increase, respectively, the distance betweenadjacent vertical struts 1122 or the distance between an adjacentvertical strut 1122 and commissure post 1108. Thus, thehorizontally-extending struts 1124 can facilitate compression of thestent portion 1102 and therefore can facilitate compression of theoverall prosthetic valve 1100. Other shapes and configurations of thestent portion are also possible. Generally, any shape or design can beprovided as the stent portion of disclosed prosthetic heart valves thatallows for radial compression and expansion of the stent portion.

FIG. 11 shows a cloth covering 1130 that can be secured to the leafletstructure 1104 such that opposing longitudinal edges of the cloth 1130are brought together to form a seam 1150 external to the leafletstructure 1104. The seam can be formed such as by suturing, adhesion,and/or other well-known cloth-edge joining techniques. The clothcovering 1130 can function to provide a substrate to which to suture theleaflets. For example, the cloth covering 1130 can be sutured around theleaflet structure 1104 and the leaflets subsequently can be sutured tothe cloth 1130 along the contour of the leaflet-supporting cusps 1114(e.g., on the outside of the leaflet-supporting cusps 1114).

A sealing ring 1146 (FIG. 11) can be sewn to the wireform cloth 1130through the leaflets in some embodiments. In some embodiments, theleaflets can be sandwiched between the wireform cloth 1130 and thesealing ring 1146, which may or may not include a cloth covering itself.FIG. 11 shows that the sealing ring 1146 can be positioned on theleaflet structure 1104 adjacent the stent portion 1102. The sealing ring1146 can be positioned between the leaflet structure 1104 and the stentportion 1102 of disclosed prosthetic heart valve frames, and can form atight seal between the frame 1100 and the native valve annulus.Additionally or alternatively, the sealing ring 1146 can provide asuture point for securing the prosthetic valve frame to the native valveannulus (in addition to or instead of using the flared stent portion toanchor the valve frame). For example, a flexible sealing ring 1146 canbe coupled to the leaflet structure 1104 in some embodiments and can beused to attach nadir sutures to the patient's annulus. In otherembodiments, the sealing ring 1146 can be provided without suturing itto the native valve tissue. The sealing ring 1146 can additionally oralternatively be configured to provide a seal positioned between theleaflet structure 1104 and the stent portion 1102 of the prostheticheart valve frame, the sealing ring 1146 being configured to enhance theeffectiveness of or replace the flexible skirt discussed above.

As noted above, disclosed embodiments can be positioned supraannularlyto a patient's native valve (e.g., the stent portion can be positionedat least partially within the annulus and at least part of the leafletstructure 1104 can be positioned supraannularly) and can be subjected topressure pushing the prosthetic valve 1100′ down towards the patient'sventricle. As noted, the cusps 1114 of the leaflet structure 1104 can beconfigured to engage with the annulus, creating a shelf to resist suchpressure. Additionally or alternatively, the flexible sealing ring 1146can be configured to rest on the native valve annulus when theprosthetic heart valve is deployed in place at the target site. Forexample, the sealing ring 1146 can have a greater diameter than thenative annulus and can thereby further resist movement or dislodgementof the valve 1100′ towards the ventricle.

While FIG. 11 does not show these components for clarity, the prostheticheart valve frame 1100′ can be provided with a plurality of leaflets,cloth coatings on the stent portion, an additional stent, and/or aflexible skirt coupled to the stent portion 1102 and configured toprevent leakage through the stent portion 1102.

FIGS. 17 and 18 illustrate additional embodiments of a prosthetic heartvalve frame. FIG. 17 shows a prosthetic heart valve frame 1701 that issimilar to the frame 501 of FIG. 7-8 except that the commissure post1708 terminates at the circumferential strut 1720 rather than extendingto the tip of the commissure support 1716 adjacent the outflow end 1712.The frame 1701 additionally includes one or more connecting segments1758 that couple the wireform portion 1704 to the stent portion 1702.Thus, in the embodiment shown in FIGS. 7-8 the commissure posts 508effectively couple the wireform portion 504 to the stent portion 502,but in the embodiment of FIG. 17, desirably only the connecting segments1758 couple the wireform portion 1704 to the stent portion 1702. Aconnecting segment 1758 can be positioned at approximately the center ofeach of the cusps 1714 in some embodiments. In other embodiments, theconnecting segments 1758 can be positioned at other locations along thecusps 1714. In some embodiments, each cusp may include two or moreconnecting segments. In some embodiments, some cusps may includeconnecting segments, while others do not.

The prosthetic heart valve frame 1701 can be configured to radiallycollapse differently than other disclosed embodiments. For example, whenthe frame 1701 is radially collapsed or compressed, the outflow end 1712(e.g., the tips of the commissure supports 1716 adjacent the outflow end1712) can move away from the stent portion 1702 along the longitudinalaxis Z. By contrast, in previously disclosed embodiments, at least partof the wireform portion can be configured to move inside the lumen ofthe stent portion as the frame is transformed to the compressedconfiguration. On the other hand, frame 1701 can effectively elongatealong the longitudinal axis Z as it is radially compressed so that thewireform portion 1704 resides completely outside the stent portion 1702when both components are compressed.

FIG. 18 shows a prosthetic heart valve frame 1800 that is similar to theframe 501 of FIGS. 7-8 except with respect to the commissure posts 508,1808, respectively. In FIGS. 7-8, the commissure post 508 extendssubstantially from the inflow end 510 to the outflow end 512,terminating at the outflow end 512 of the commissure support 516. Bycontrast, the commissure post 1808 in FIG. 18 does not extend all theway to the outflow end 1812 of the commissure support 1816. Instead, thecommissure post 1808 extends only to a T-shaped termination 1856. TheT-shaped termination 1856 can be positioned approximately equidistantfrom the circumferential strut 1820 and the outflow end 1812. In otherembodiments, the T-shaped termination 1856 can be positioned higher orlower along the commissure support 1816 (e.g., closer to the outflow end1812 as shown in FIG. 18, or closer to the circumferential strut 1820).In this embodiment, leaflet tabs can be configured to extend through thewindow 1860 created by the T-shaped termination. Thus, rather thanwrapping leaflet tabs around the commissure post 1808, the leaflet tabscan be secured to the frame 1800 via techniques more similar toconventional surgical valves.

Disclosed embodiments of a prosthetic heart valve frame can comprise anymaterial that allows the frame to be radially collapsible andexpandable. Preferable materials allow for slight flexion of at least aportion of the frame in response to pulsatile loading. Examples ofsuitable materials for forming the overall frame (e.g., the stentportion and/or the wireform portion) include superelastic materials suchas Nitinol or NiTiCr, as well as stainless steel, cobalt, chromium,titanium, or alloys or combinations of the same (e.g., CoCr alloys).Some embodiments can comprise a flexible biocompatible polymer, such aspolypropylene or silicon. Different frame materials can be selecteddepending on the method of deployment. For example, the frame cancomprise a superelastic material for self-expanding embodiments, or aplastically deformable material such as CoCr for plastically expandableembodiments (e.g., embodiments that are deployed via balloon expansion).

Leaflet Attachment

FIG. 15 illustrates a section view of prosthetic heart valve frame 1100,taken along line 15-15 in FIG. 11, but with two leaflets 1528 a, 1528 bvisible in order to illustrate one method of leaflet attachment. Asshown in FIG. 15, at least a portion of upright strut 1108 and/orleaflet structure 1104 can be covered with cloth 1130. The leaflets 1528a, 1528 b can be provided with tabs 1532 a, 1532 b on opposing ends ofthe leaflets 1528 a, 1528 b (although only one end of each leaflet 1528a, 1528 b is visible in FIG. 15). Each tab 1532 a, 1532 b can passbetween an upright strut 1108 and a portion of a leaflet structure 1104near the outflow end 1112, in a direction from the lumen 1106 outwards.For example, a portion of the leaflet structure 1104 adjacent theoutflow end 1112 can be substantially vertical, thereby forming acommissure support 1116, such that a leaflet tab 1532 a, 1532 b can bepositioned between the upright strut 1108 and the commissure support1116 on each side of the upright strut 1108.

The tabs 1532 a, 1532 b of adjacent leaflets 1528 a, 1528 b can bewrapped at least partially around an upright strut 1108 and coupledtogether, such as by one or more sutures 1534. Coupling the leafletstogether in this manner can position the suture securing the leaflets(e.g., a weak point of the valve) away from the greatest stresses due tophysiologic loading, thereby minimizing the risk of leaflet failure atthe suture point.

Furthermore, using the upright struts 1108 for leaflet attachment cansimplify valve construction in some embodiments. For example, while someconventional surgical valves require polyester inserts in order toprevent the leaflets from being pulled through the commissure supportsduring pressure loading, the presently disclosed attachment methods andstructures can ensure that the leaflets 1528 are not pulled through thecommissure supports without requiring such inserts. However, someembodiments can include an insert or polymer stent piece at the point ofleaflet attachment, as shown in FIG. 16.

FIG. 16 illustrates a section view of a leaflet attachment arrangementsimilar to that shown in FIG. 15, except that the embodiment of FIG. 16includes additional sutures 1644 and also an additional insert orpolymer (e.g., polyester) stent piece 1636 positioned between the cloth1130 covering the upright strut 1108 and the sutured tabs 1632 a, 1632 bof the leaflets 1628 a, 1628 b. The polyester stent piece 1636 can, insome embodiments, carry at least a part of the leaflets' load and cansubstantially prevent the leaflets 1628 from pulling through the leafletstructure 1104 adjacent the commissure support 1116, in the case of, forexample, fracture of an upright strut 1108.

As shown in FIGS. 15-16, leaflets can be attached to disclosedembodiments of a collapsible prosthetic heart valve in ways similar toleaflet attachment for conventional surgical valves. However, thedisclosed embodiments can allow for radial compression of the prostheticheart valve, unlike surgical valves.

Additional details regarding suitable methods of leaflet attachment arediscussed in U.S. Patent Application Publication No. 2011-0276128 to Cao(the “Cao application”), which is incorporated herein by reference.

Overview of Prosthetic Valve Having a Two-Piece Valve Frame

FIG. 19 shows a prosthetic heart valve 600, which generally includes astent portion 602 and a wireform portion 604. The stent portion 602 andthe wireform portion 604 can be separate components from one another,such that no metal couples the two structures in some embodiments, thusforming a two-piece valve frame. In some embodiments, the stent portion602 and the wireform portion 604 are only coupled together by one ormore non-metallic devices or components, such as one or more of a clothcovering, a flexible skirt, a flexible leaflet support stent, and/or asealing ring. In some embodiments, the stent portion 602 can beballoon-expandable, while the wireform portion 604 can be formed from ashape memory material.

The stent portion 602 can be formed of a plurality of vertical andhorizontally-extending struts 622, 624, and the wireform portion 604 caninclude leaflet-supporting cusps 614 and commissure supports 616. Theprosthetic valve 600, which is shown in an expanded configuration inFIG. 19, can also include a plurality of leaflets 628, a flexible skirt638 (shown partially broken away), a sealing ring 646 (shown partiallybroken away), a leaflet support stent 652 (shown partially broken away),and a cloth covering 630 (shown partially broken away) over the wireformportion 604, each of which will be described in further detail below.

FIG. 20 shows the prosthetic heart valve 600 implanted within apatient's native valve annulus 648 (e.g., aortic valve annulus 648). Asshown, the prosthetic valve 600 can be implanted such that at least aportion of the valve 600 is positioned supraannularly. For example, thewireform portion 604 can be positioned supraannularly, while the stentportion 602 is configured to anchor the prosthetic valve 600 in placewithin the native valve annulus 648. The stent portion 602 can beslightly flared outward at the inflow end 610, such that the stentportion 602 frictionally engages the native valve annulus 648 to preventmigration of the prosthetic valve 600. Additionally or alternatively, anoptional sealing ring 646 can be provided adjacent the wireform portion604. Said sealing ring 646 can be configured to engage the shelf 653 ofthe native valve annulus 648 so as to prevent migration of theprosthetic valve 600 into the ventricle 650. The sealing ring 646 canalso create a seal around the prosthetic valve 600 such thatsubstantially no blood can pass between the native valve annulus 648 andthe prosthetic valve 600.

Thus, disclosed embodiments can be positioned supraannularly to apatient's native valve (e.g., the stent portion can be positioned atleast partially within the annulus and at least part of the wireformportion can be positioned supraannularly). In this position, aprosthetic valve may experience significant pressure during diastole,which can push the prosthetic valve down towards the ventricle. Thecusps of the wireform portion can be configured to engage with theannulus, creating a shelf to resist such pressure (e.g., the cusps ofthe wireform portion can have a greater diameter than the nativeannulus). Additionally or alternatively, the optional flexible sealingring can be configured to rest on the native annulus when the prostheticheart valve is deployed in place at the target site. For example, thesealing ring can have a greater diameter than the native annulus and canthereby further resist movement or dislodgement of the valve towards theventricle.

Components of the prosthetic valve 600 will now be described in greaterdetail.

Leaflets

Returning to FIG. 19, the wireform portion 604 can comprise a pluralityof cusps 614 configured to engage with a respective valve leaflet 628.For example, prosthetic valve 600 includes three cusps 614, each of thecusps 614 being configured to engage with one of three leaflets 628secured to prosthetic valve 600. For example, leaflets can be secured tothe cusps 614 in a manner similar to conventional surgical valves, withthe leaflets being sutured to the cloth covering 630 surrounding thecusps 614. In this manner, the leaflets 628 can open when exposed to apositive pressure gradient in a fluid (e.g., blood) passing between theinflow end 610 and the outflow end 612 and close (or coapt) when exposedto a negative pressure gradient between the inflow end 610 and theoutflow end 612. When the leaflets 628 are closed, as shown in FIG. 19,they can be configured to retain a central hole 654 through the centerof the leaflets 628 when the valve 600 is at rest (e.g., not subject toany pressure gradient). When the leaflets 628 are subjected to apressure gradient (e.g., after implantation in a patient's native valveannulus) the leaflets can be configured to close completely such thatsubstantially no blood leaks through the closed leaflets duringdiastole. By contrast, conventional prosthetic valves configured to beradially compressed for delivery disadvantageously must be configuredsuch that the leaflets close completely when the valve is at rest.

For illustration purposes, the leaflets 628 are shown with coupling tothe prosthetic valve 600 still in progress. The leaflets 628 can eachinclude tabs 632 at opposing ends of the leaflets. The tabs 632 canfacilitate coupling of the leaflets 628 to the wireform portion 604. Forexample, as will be explained in further detail below in connection withFIGS. 34-35, each tab 632 can extend through an extension of one of theleaflet-supporting cusps 614 adjacent the outflow end 612 (e.g., througha respective commissure support 616). Adjacent tabs 632 can be at leastpartially wrapped around a post of the leaflet support stent 652 andcoupled together (e.g., with sutures) around the polymer stent 652. Theleaflets can additionally be secured to the frame such as by beingsutured to the cloth covering 630 surrounding the cusps 614.

Examples of suitable materials for forming the valve leaflets includepericardial tissue (e.g., bovine, porcine, or cadaver pericardialtissue), biocompatible synthetic polymers, and any other suitablenatural or synthetic material. While three leaflets are shown, variousembodiments can comprise one, two, three, or more leaflets.

Flexible Skirt

In addition to leaflets, the prosthetic valve 600 can include a flexibleskirt 638. The flexible skirt 638 can be, for example, a polyesterfabric (e.g., Dacron) skirt. The flexible skirt 638 is shown coupled tothe inner surface of the stent portion 602 (e.g., positioned within alumen 606 of the stent portion 602) and can be configured to preventleakage through the stent portion 602 once the prosthetic valve 600 isimplanted within a patient's native valve. In the specific embodimentshown, the flexible skirt 638 can be coupled to one or more of thevertical struts 622, such as to circular portions 640 adjacent thecircumferential strut 620 (e.g., with sutures 642). In otherembodiments, skirt 638 can be coupled to the stent portion 602 inadditional places and/or in alternative arrangements. In someembodiments, the skirt 638 can be coupled to a cloth coveringsurrounding the stent portion 602

While FIG. 19 shows the skirt 638 positioned within the lumen 606 of theprosthetic valve 600, in some embodiments, skirt 638 can be positionedon the outer surface of the stent portion (e.g., outside of the lumen606). In some embodiments, the prosthetic valve 600 can include a skirton both the inside and outside surfaces of the stent portion 602. Inalternative embodiments, the prosthetic valve can be provided without aflexible skirt 638.

While FIG. 19 shows only a cut-away view of the skirt 638, the skirt 638can extend around the entire circumference of the stent portion 602.Additionally, as shown, the skirt 638 can be essentially the same heightas the stent portion 602. For example, the skirt 638 can extendsubstantially from an inflow end 610 and towards an outflow end 612,terminating, in some embodiments, at cusp portions 614, oralternatively, adjacent a circumferential strut 620 positioned near thewireform portion 604. Thus, the skirt 638 can substantially cover theentire stent portion 602 and optionally the area of the wireform portionbelow the cusp portions 614. In alternative embodiments, the skirt 638can be configured to only cover a portion of the stent portion 602.

In some embodiments, the flexible skirt 638 can extend up to meet thecloth covering 630 on the wireform portion 604 so that there is no gapbetween them. The flexible skirt 638 can be coupled to the clothcovering 630 so as to not impede movement of the leaflets 628 or cusps614. The flexible skirt 638 can be coupled to the stent portion 602, thecircumferential strut 620, and/or the cloth covering 630 on the wireformportion 604 so as not to impede such movement of the cusps 614. In someembodiments, the flexible skirt 638 can follow the contour of thecommissure supports 616 such that everything below the leaflets 628 issubstantially sealed off.

Cloth Covering

The cloth covering 630 can be secured to the wireform portion 604 suchthat opposing longitudinal edges of the cloth 630 are brought togetherto form a seam external to the wireform portion 604 (see seam 954 inFIG. 33). The seam can be formed such as by suturing, adhesion, and/orother well-known cloth-edge joining techniques. The cloth covering 630can function to provide a substrate for suturing the leaflets to. Forexample, the cloth covering 630 can be sutured around the wireformportion 604 and the leaflets subsequently can be sutured to the cloth630 along the contour of the leaflet-supporting cusps 614 (e.g., on theoutside of the leaflet-supporting cusps 614). The cloth 630 can alsoprevent the leaflets from contacting the metal of the leaflet-supportingcusps 614 and commissure supports 616, thereby potentially decreasingwear on the leaflets. Cloth covering 630 can comprise any suitablebiocompatible material, such as polyester or polyethylene terephthalate.

Sealing Ring

The prosthetic heart valve 600 can include a flexible sewing ring orsealing ring structure 646, such as a tri-lobular sealing ring. Thesealing ring 646 can be arranged such that sinus-shaped portions of thering can be aligned with the cusps 614 of the wireform portion 604. Thesealing ring 646 can form a tight seal between the wireform portion 604and the stent portion 602 of disclosed prosthetic heart valve frames,can form a tight seal between the prosthetic valve and native valveannulus, and/or can provide a suture point for securing the prostheticvalve frame to the native valve annulus (in addition to or instead ofusing the flared stent portion to anchor the valve frame).

The sealing ring 646 can be sewn to the wireform cloth 630 through theleaflets 628 in some embodiments. In some embodiments, the leaflets 628can be sandwiched between the wireform cloth 630 and the sealing ring646, which may or may not include a cloth covering itself. The sealingring 646 can be coupled to a leaflet support stent 652, around whichleaflet tabs 632 can be wrapped and secured. FIG. 19 shows that thesealing ring 646 can be positioned on the wireform portion 604 adjacentthe stent portion 602. The sealing ring 646 can form a tight sealbetween the wireform portion 604 and the stent portion 602 of disclosedprosthetic heart valve frames, and/or can provide a suture point forsecuring the prosthetic valve frame to the native valve annulus (inaddition to or instead of using the flared stent portion to anchor thevalve frame). For example, a flexible sealing ring 646 can be coupled tothe wireform portion 604 in some embodiments and can be used to attachnadir sutures to the patient's annulus. In other embodiments, thesealing ring 646 can be provided without suturing it to the native valvetissue. The sealing ring 646 can additionally or alternatively beconfigured to provide a seal positioned between the wireform portion 604and the stent portion 602 of the prosthetic heart valve frame, the sealbeing configured to enhance the effectiveness of or replace the flexibleskirt discussed above.

Frame Structure

Embodiments of a frame for use with a prosthetic heart valve will now bedescribed. FIG. 21 illustrates the frame 601 of the prosthetic heartvalve 600 of FIG. 19, with the frame still in its expandedconfiguration. FIG. 23 illustrates the frame 601′ in a collapsedconfiguration (e.g., for delivery). The frame 601, 601′ is shown withouta plurality of leaflets, a cloth covering over a portion of the frame, asealing ring, or a fabric or flexible skirt of another material, inorder to provide a clear view of the frame.

As shown in FIG. 21, frame 601 can comprise a stent portion 602 and awireform portion 604 (wireform portion 604 is also referred to as aleaflet support portion). In particular embodiments, the stent portion602 and the wireform portion 604 are separate components in that theyare not connected to each other by any metallic components, such asmetal struts or welds. In such embodiments, the stent portion 602 can becoupled to the wireform portion 604 via other components of the valve,as further described below.

Generally, the stent portion 602 can be configured to anchor the frame601 to a patient's native valve annulus and the wireform portion 604 canbe configured to receive and support at least one valve leaflet. Forexample, once the prosthetic valve 600 is positioned at an implantationsite, the stent portion 602 can engage an inner periphery of a bodylumen (e.g., a native annulus) at the implantation site. Disclosedembodiments can engage with the native annulus via the stent portion 602and/or a sealing ring, such as by engaging the aortic annulus, thefibrous annulus, or the aorta wall (e.g., a position downstream from thelocation of the native leaflets).

The stent portion 602 can define a lumen 606 therethrough. The stentportion 602 can comprise any suitable combination of struts and wiresthat can allow the stent portion to radially collapse to a compressedconfiguration for delivery and expand to an expanded configuration foroperation at the implantation site. The configuration of struts andwires of the stent portion can also facilitate anchoring of the frame601 within a patient's native valve.

As shown in FIGS. 21 and 23, the inflow end 610 corresponds to the end610 of the stent portion 602 opposite the wireform portion 604. Theoutflow end 612 corresponds to the end 612 of the wireform portion 604opposite the stent portion 602.

In some specific embodiments, each of the cusps 614 can include athinned portion 615 (FIG. 21) configured to facilitate compression ofthe wireform portion 604. Each cusp 614 can include one or more thinnedportions 615 that can be configured to provide the cusps 614 withgreater flexibility, especially near the thinned portions 615. Forexample, the thinned portion 615 can be configured to deform morereadily than the adjacent, thicker, areas of the cusps 614. In someembodiments, the thinned portions 615 can be positioned substantiallynear the center of each cusp, but other configurations are alsosuitable. For example, each cusp 614 could include at least two thinnedportions 615 spaced apart from each other along the cusp 614. Thethinned portions 615 can, for example, serve as a hinge and facilitatebending of the cusps 614 during transformation of the wireform portion604 (and the frame 601 as a whole) from the expanded configuration shownin FIG. 21 to a compressed configuration, such as the configurationshown in FIG. 23.

As shown in FIG. 21, in an expanded configuration, the cusps 614 can bespaced apart from the stent portion 602 along a longitudinal directiondefined by the lumen 606 of the stent portion 602. For example, thecusps 614 can be spaced apart from the stent portion 602 along thelongitudinal axis Z in the shown expanded configuration (FIG. 21).Additionally or alternatively, the cusps 614 can be positioned furtheroutward radially than the stent portion 602 when in the expandedconfiguration. For example, the cusps 614 can have a greater diameter inthe expanded configuration than the circumferential strut 620. In thisconfiguration, the cusps 614 can engage the native valve annulus (e.g.,the shelf 653 of annulus 648 seen in FIG. 20).

Adjacent cusps 614 can be coupled to one another at each of a pluralityof commissure supports 616 adjacent the outflow end 612. For example,adjacent cusps 614 a and 614 b can be coupled to one another atcommissure support 616 a as shown in FIG. 23. Similarly, adjacent cusps614 a and 614 c can be coupled to one another at commissure support 616b, and adjacent cusps 614 b and 614 c can be coupled to one another atcommissure support 616 c.

The commissure supports 616 can lean slightly outward relative to thelumen 606 (e.g., outward relative to the central flow axis Z of theprosthetic valve frame 601) when the valve is at rest. The commissuresupports 616 can alternatively be oriented to lean inwardly at a slightangle relative to the longitudinal axis Z. Alternatively, the commissuresupports 616 can be substantially vertical (e.g., substantially parallelto the central flow axis) when the valve is at rest, as shown in FIG.21.

At least part of the wireform portion 604 can be configured to undergoflexion (e.g., can be configured to move slightly) during normalphysiologic loading when implanted in a patient's native valve. Forexample, as shown in FIG. 22, the commissure supports 616 (e.g., thefree end of the commissure supports 616 adjacent the outflow end 612)can be configured to flex in the direction indicated by arrow 618 (e.g.,radially inward) during each cardiac cycle, and likewise can beconfigured to move radially outward, returning to their originalpositions later in each cardiac cycle.

The prosthetic valve frame 601 can be positioned at the implantationsite such that the cantilevered commissure supports 616 can deflectindependently of the surrounding body lumen to which the valve frame 601is secured. The ability of the commissure supports 616 to flex in thismanner can allow the leaflets supported by the commissure supports 616and cusps 614 to close more gently, thereby relieving stress on theleaflets during diastole.

In some embodiments, the wireform portion 604 can be thinner than wouldnormally be expected, in order to optimize the movement (e.g., flexion)during pulsatile in vivo loading. Such flexion can contribute to thelongevity and durability of disclosed prosthetic heart valve frames 600.The stiffness of the wireform portion 604 can be optimized such that thecommissure supports 616 deflect under physiologic loading.

In some embodiments, the commissure supports 616 can be configured todeflect an amount similar to that of conventional surgical valves and anamount greater than that of conventional transcatheter valves. Forexample, while a conventional transcatheter valve may only flex tens ofmicrons or less, the presently disclosed valve frames can flex up toaround 1 mm or more, with flexion varying slightly with different sizedvalve frames. Thus, the presently disclosed prosthetic heart valveframes can flex about 10-100 times more than conventional transcathetervalves.

For example, FIG. 22 shows the deflection of a commissure support 616under physiologic loading. The commissure support 616 can move in acantilevered fashion radially inward and outward during each cardiaccycle. As shown in FIG. 22, the commissure support 616 can deflectradially inward a distance a. In some embodiments, a can be about 1 mmor greater.

Such flexion can be adjusted and optimized to improve hemodynamicsthrough the valve. For example, as a result of this greater flexion, theleaflets can advantageously be arranged to retain a central hole (e.g.,the three pointed star-shaped hole 654 seen in FIG. 19 where theleaflets meet in the center of the valve) when the valve is at rest(i.e., not subjected to any pressure gradient). Under physiologicloading (and flexion of the commissures), the central hole is closedcompletely, but the leaflets generally come together in a controlled,gentle fashion. On the other hand, conventional transcatheter valvestypically cannot have such a central hole in the leaflets—the leafletsmust be completely closed when the valve is at rest, because the valveis unable to flex significantly. As a result, the leaflets oftraditional transcatheter valves tend to collide together moreforcefully, which can disadvantageously reduce the lifespan of theprosthetic valve.

Returning to FIG. 21, the stent portion 602 of the frame 601 can beflared outward in its expanded configuration near the inflow end 610.For example, the diameter of the lumen 606 at the inflow end 610 of thestent portion 602 can be greater than the diameter of the lumen 606 ofthe stent portion 602 adjacent the wireform portion 604, therebycreating a flared stent portion 602. The flared configuration of thestent portion 602 can facilitate anchoring of the stent portion 602within the patient's native valve annulus without the use of sutures (orwith a reduced number of sutures as compared with conventionalprosthetic heart valves). For example, as shown in FIG. 20, the flaredstent portion 602 can engage with the valve annulus 648, keeping theframe 601 in position, with the wireform portion 604 being positioneddistal to the annulus. Therefore, in some embodiments, at least part ofthe wireform portion 604 does not contact the native valve annulus oncethe frame 601 is implanted. For example, in some embodiments, the cusps614 and/or a sealing ring may contact the native valve annulus, whilethe commissure supports 616 do not.

In some embodiments, the leaflet-supporting cusps 614 can protruderadially outward past the stent portion 602 (or at least past the upperend of stent portion 602 adjacent the cusps 614) so as to form an edgeor shelf which can further discourage migration of the prosthetic heartvalve frame 601 during diastole (e.g., the shelf formed by the cusps 614could engage with or rest against the native annulus, thereby workingtogether with the flared stent portion to prevent migration of the valveframe into the ventricle). In other words, the flared lower end of thestent portion 602 can be positioned on one side of the native annulusand can have a diameter larger than the annulus to prevent migration inone direction, while the cusps 614 can be positioned on the oppositeside of the annulus and can have a diameter larger than the annulus toprevent migration in the opposite direction. For example, in embodimentswhere the wireform portion 604 comprises Nitinol or another superelasticmaterial (e.g., shape memory materials), the cusps 614 can be shape setsuch that they are positioned further out radially than at least the endof stent portion 602 adjacent the wireform portion 604 in the expandedconfiguration.

In some embodiments, such as seen in FIG. 21, the frame 601 can includeone or more circumferential struts 620. The circumferential strut 620can be positioned on the stent portion 602 adjacent the wireform portion604 and can be configured to increase the radial stiffness of the stentportion 602. Circumferential strut 620 can follow the curvature of theupper end of the stent portion 602 when the stent portion 602 is in itsexpanded configuration and can be bent or folded when the stent portion602 is in its compressed configuration (a series of bent sections asshown in FIG. 21 between vertical struts 622 can be provided thatcollapse or fold between the vertical struts 622 to facilitate crimpingof the stent portion 602). The circumferential strut 620 can essentiallyserve as a boundary between the stent portion 602 and the wireformportion 604.

Further, the circumferential strut 620 can serve to limit the diameterof the stent portion 602 adjacent the wireform portion 604 in theexpanded configuration. For example, the circumferential strut 620 canlimit the diameter of the stent portion 602 at the end of the stentportion opposite the inflow end 610 so that it is no greater than theexpanded diameter of the wireform portion 604. This can preventover-expansion of the outflow end 612 of the stent portion 602 and thewireform portion 604. In some embodiments, the circumferential strut 620can be a single continuous strut around the circumference of the stentportion 602. In some embodiments, the circumferential strut 620 cancomprise a plurality of smaller struts positioned between adjacentvertical stent struts 622.

The stent portion 602 can include a plurality of vertical struts 622that extend from the inflow end 610 towards the circumferential strut620, if present. At least one row of horizontally-extending struts 624can be positioned around the circumference of the stent portion 602,extending between adjacent vertical struts 622. FIG. 21 shows three rowsof horizontally extending struts 624, but more or fewer rows are alsopossible. In the specific embodiment shown, the horizontally-extendingstruts 624 can be substantially U-shaped or V-shaped, with the curvedportion or vertex portion 626 pointing towards the outflow end 612 ofthe frame 601. Bending or extending of the horizontally-extending struts624 can decrease or increase, respectively, the distance betweenadjacent vertical struts 622. Thus, the horizontally-extending struts624 can facilitate compression and expansion of the stent portion 602.In some embodiments, different rows of horizontally-extending struts 624can be configured to expand different amounts, so as to facilitate theflared portion of the stent portion 602 near the inflow end 610. Forexample, the row or rows nearest the inflow end 610 can be configured toexpand, elongate, or straighten more than the other row or rows ofhorizontally-extending struts, thereby allowing a portion of the stentportion 602 near the inflow end 610 to be flared outwards as shown inFIG. 21.

Other shapes and configurations of the stent portion are also possible.Generally, any shape or design can be provided as the stent portion ofdisclosed prosthetic heart valves that allow for radial compression andexpansion of the stent portion. Embodiments of various stent portionscan include more or fewer horizontal and/or vertical struts than areshown in the drawings. Locations, orientations, and numbers of strutscan be varied to alter radial force exerted by the pre-crimped stentportion and to optimize fatigue resistance in particular embodiments.

FIGS. 23-24 show the valve frame 601 in a collapsed configuration 601′(e.g., radially compressed for delivery). FIG. 24 shows the collapsedframe 601′ next to the expanded frame 601 for an example of one relativesize difference between the two configurations. In one specific example,a prosthetic valve frame can be collapsed from a 25 mm size to a 14 mmoutside diameter for delivery. For example, both the stent portion andthe wireform portion can be collapsed to 14 mm outer diameter or less.The wireform portion can be collapsed radially to the same diameter as apre-crimped stent portion in some embodiments.

As shown in FIG. 23, when the valve frame 601′ is radially compressed(or when the frame 601′ is in a pre-crimped collapsed configuration),the circumferential strut 620 can become pinched into V-shaped sectionsbetween adjacent circular openings 640. Further, adjacent verticalstruts 622 can move closer to one another as the frame 601′ is collapsed(or can be closer to one another as compared to the expandedconfiguration). While FIG. 23 does not show thinned portions (e.g.,thinned portions 615 shown in FIG. 21), in some embodiments, thinnedportions of the cusps can also facilitate compression or crimping of theframe 601′ to a reduced diameter for delivery.

In some embodiments, the stent portion 602 can comprise aballoon-expandable material and can be rigid or stiff enough toconstrain at least the cusps 614 of the wireform portion 604 in itscollapsed state without any external constraints on the wireform portion604, such as a sheath or band around the wireform portion. For example,in embodiments where the wireform portion 604 comprises a shape memorymaterial (e.g., Nitinol) and the stent portion 602 comprises a balloonexpandable material, the wireform portion 604 can be secured to thestent portion 602 by sutures, a sealing ring, a leaflet support stent,cloth coverings, and/or some other coupling arrangement. Whatever thecoupling, it can be configured such that at least the cusps 614 of thewireform portion 604 cannot be expanded beyond the stent portion 602.Furthermore, the stent portion 602 can be stiff enough in its compressedconfiguration that it can remain compressed despite any tendency of thewireform portion 604 to move to its unstressed, expanded configuration.Thus, the stiffness of the stent portion 602 can substantially preventat least the cusps 614 of the wireform portion 604 from expandingwithout any external restraining device on the wireform portion 604.Additionally or alternatively, an external sheath or other restrainingdevice can be used to retain at least a portion of the wireform portion604 in its crimped configuration. For example, in some embodiments, arestraint can be positioned around all or a portion of the wireformportion. In some embodiments, a restraint can be positioned around thecommissure supports 616 of the wireform portion in order to preventpremature expansion of the wireform portion 604

Once the prosthetic valve has been positioned within a patient's valve,the balloon-expandable stent portion 602 can be expanded. As the stentportion 602 is expanded, the wireform portion 604 follows. For example,the wireform portion 604 can expand to the extent the stent portion 602allows it to expand.

FIGS. 25 and 26-27 illustrate alternative collapsed configurations fordisclosed embodiments of a prosthetic heart valve. For example, as shownin FIG. 25, a prosthetic heart valve frame 700 that includes a stentportion 702 and a wireform portion 704 can be compressed such that thestent portion 702 takes on a conical shape. In this embodiment, aportion of the stent portion 702 adjacent the inflow end 710 can becompressed more than a portion of the stent portion 702 adjacent thecusps 714 of the wireform portion (e.g., at the circumferential strut720). Thus, the diameter of the stent portion 702 adjacent the inflowend 710 can be less than the diameter of the stent portion 702 adjacentthe wireform portion 704, in some compressed configurations. Bycomparison, the stent portion 602 of FIG. 23 is substantiallycylindrical when compressed, with the diameter of the stent portion 602adjacent the inflow end 610 being substantially equal to the diameter ofthe stent portion 602 adjacent the cusps 614 of the wireform portion604. In some embodiments, the frame 700 can be cut or formed in apre-crimped, substantially cylindrical collapsed configuration, and thenfurther crimped into a conical configuration as shown in FIG. 25.

As shown in FIGS. 26-27, in some embodiments, the tips of the commissuresupports 1216 can be radially compressed more than other areas of thewireform portion 1204. For example, the commissure supports 1216 can beradially compressed towards each other adjacent the outflow end 1212,while the compressed diameter of the wireform portion 1204 can increasetowards the cusps 1214 adjacent the stent portion 1202. In someembodiments, the cusps 1214 can extend slightly farther radially outwardthan the stent portion 1202, adjacent the circumferential strut 1220 andthe circular portions 1240. In the embodiments shown, the cusps 1214 donot extend any farther radially outward than the stent portion 1202adjacent the circumferential strut 1220. In some embodiments, the lowestpoints of the cusps 1214 opposite the outflow end 1212 can be positionedslightly longitudinally lower than the circumferential strut 1220 suchthat the cusps 1214 overlap the stent portion 1202 slightly. In otherembodiments, the lowest points of the cusps 1214 opposite the outflowend 1212 can be positioned directly adjacent to or slightlylongitudinally higher than the circumferential strut 1220 such that thecusps 1214 do not overlap the stent portion 1202 at all. The stentportion 1202 can be pre-crimped or compressed to a substantiallycylindrical configuration as shown in FIG. 26, or to a substantiallyconical configuration as shown in FIG. 25.

Disclosed embodiments of a prosthetic heart valve frame can comprise anymaterial that allows the frame to be radially collapsible andexpandable. Preferable materials allow for slight flexion of at least aportion of the frame in response to pulsatile loading. Examples ofsuitable materials for forming the wireform portion include superelasticmaterials such as Nitinol, NiTiCo, NiTiCr, or alloys or combinationsthereof. Examples of suitable materials for forming the stent portioninclude plastically deformable materials (e.g., balloon expandablematerials) such as stainless steel, cobalt, chromium, titanium, oralloys or combinations of the same (e.g., CoCr alloys). Some embodimentscan comprise a flexible biocompatible polymer, such as polypropylene orsilicone.

Leaflet Attachment Subassembly

FIGS. 28-35 and FIGS. 40-42 illustrate components of a subassembly forattaching one or more leaflets to the prosthetic heart valve framedescribed above. A flexible polymer stent 1470, also referred to hereinas a leaflet support stent 1470 (FIGS. 28-29), and a sealing ring insert880 (FIG. 30) can be joined and covered by a rolled covering cloth.Alternatively, a leaflet support stent 2600 (FIGS. 40-42) and thesealing ring insert 880 (FIG. 30) can be joined and covered by a rolledcovering cloth. The sealing ring insert 880 and the adjacent cloth canbe suture permeable (e.g., sutures can extend through the sealing ring)and can provide an attachment region for attaching the stent portion tothe wireform portion of a prosthetic valve.

Referring to FIG. 28, the flexible stent 1470 is shown in a neutralposition. In FIG. 29, the flexible stent 1470 is shown in alongitudinally collapsed position. The illustrated stent 1470 defines aninterior, substantially cylindrical volume 1471 defining a longitudinalaxis 1472 of the stent. The flexible stent 1470 comprises acircumferentially extending base member 1473. As shown, some basemembers 1473 can define longitudinally displaced undulations 1474relative to, and positioned between, adjacent cusps 1475. Each of aplurality of posts 1476 extends longitudinally from a proximal end 1477adjacent a respective undulation 1474 to a distal end defining a posttip 1479. In some instances, such a stent 1470 can be formed from anyflexible biocompatible polymer, such as, for example, polypropylene. Inanother implementation, the stent 1470 can be made of silicone with orwithout a cloth core

The primary functions of the stent 1470 are to provide additionalsupport structure for supporting the leaflets in the tricuspidconfiguration under working conditions and to provide a structure towhich the sealing ring can be attached. The stent is also sufficientlyflexible to allow the valve to be longitudinally and/or radiallycollapsed to a smaller configuration for delivery.

The stent 1470 can undergo high levels of strain without sufferingplastic deformation or other damage. For example, FIG. 29 illustrates anisometric view of the stent 1470 in a longitudinally collapsed position.In the illustrated position, each of the post tips 1479 has been foldedradially inward from their respective neutral positions (FIG. 28) andtoward the longitudinal axis 1472 of the stent. In its longitudinallycollapsed position, the stent 1470 can form a substantially conicallyshaped interior volume 1471′, as shown in FIG. 29. Although notillustrated, the stent 1470 can also be radially collapsed in a mannersimilar to the wireform 1204, as shown in FIGS. 26 and 27.

With reference to FIG. 30, an example of a sealing ring insert 880 willnow be described. The body 881 of the illustrated sealing ring insert880 comprises a frustoconical, annular body-of-rotation. In other words,the illustrated sealing ring body 881 defines a body of rotation about asealing ring axis 882 extending longitudinally of the body. The body 881defines a major circumference 883 having a major diameter and a minorcircumference 884 having a minor diameter, and a tapering wall 885extending between the major circumference 883 and the minorcircumference 884. The wall 885 can have a relatively smooth (i.e.,untextured) inner surface 886. The wall can have an outer surface 887that is roughened, or provided with retention features (e.g., ridges,including barbs 888).

The illustrated ridges 888 formed by the outer surface 887 can providethe sealing ring portion 880 with an uneven outer contour that canengage the surrounding tissue of the implantation site. Such engagementcan provide the prosthetic valve with improved purchase at theimplantation site. For example, the taper of the wall 885 can facilitateplacement at a desired implantation site as the minor circumference 884first comes into contact with the surrounding tissue of the lumen. Asthe sealing ring 880 is urged longitudinally into the lumen, the tissuecan expand and slide longitudinally of the outer surface 887. The barbsor other retention features 888 can engage the surrounding tissue and atleast partially retain the sealing ring 880 within the surroundinglumen. The sealing ring can be secured in place by suturing in someembodiments, but such suturing is advantageously not required in someembodiments.

In addition, such ridges 888 can stiffen the sealing ring insert 880,adding to its resiliency. Even so, the sealing ring 880 preferably isflexible for allowing the prosthetic valve to collapse (e.g.,longitudinally and/or radially collapse). In some embodiments, thesealing ring insert 880 comprises a silicone-based material, althoughother suture-permeable materials can be used.

A stent covering cloth (e.g., a substantially cylindrical or tubularcloth) can be axially aligned with the flexible stent 1470 and thesealing ring insert 880. In other words, the longitudinal axis of thecovering cloth can be co-axially aligned with the respectivelongitudinal axes 1472, 882 of the stent 1470 and the sealing ring 880.The covering cloth can comprise any suitable biocompatible fabric.

The whole of the stent 1470 can be inserted into the interior of thetubular cloth. The sealing ring insert 880 can also be inserted into theinterior of the tubular cloth. As best shown in FIG. 31, the sealingring insert 880 and the stent 1470 can be co-centrically positioned withrespect to each other such that the sealing ring 880 circumscribes thebase 1473 of the stent 1470. The minor circumference 884 of the sealingring 880 can be aligned with the lower edge of the base 1473 of thestent 1470.

Once the stent 1470 and the sealing ring insert 880 have been positionedwithin the tubular cloth, a free end portion of the cloth can be foldedinwardly on itself. In other words, a “top” edge can be rolled inwardlytoward the tube's interior and pulled through the cylindrical interior1471 of the stent 1470 so as to line both the interior and exteriorsurfaces of the stent 1470 with the cloth and to juxtapose the opposingends of the tubular cloth. FIG. 31 shows the completed subassembly 1700of the flexible polymer stent 1470, the sealing ring 880, and the clothcovering 1790. The subassembly 1700 can be secured to a wireform portionand/or stent portion of a prosthetic heart valve, as will be describedbelow.

FIGS. 40-42 illustrate an alternative embodiment of a subassembly 2700(FIG. 41) that can be used in place of the subassembly 1700. FIG. 40shows a leaflet support stent 2600 that includes a stent frame 2602 anda plurality of commissure tips 2604. The stent frame 2602 can be, forexample, a flexible (e.g., radially compressible) stent framecomprising, for example, Nitinol or other superelastic material. Thecommissure tips 2604 can comprise, for example, a biocompatible polymersuch as a polyester.

The stent frame 2602 comprises a continuous ring shaped to include threecusp support portions 2614 and three commissure portions 2608 spacedapart from one another, with a commissure portion 2608 positionedbetween each pair of adjacent cusp portions 2614. A commissure tip 2604can be secured to each of the commissure portions 2608 of the stentframe 2602. For example, the commissure tips 2604 can each include oneor more sewing holes 2606 through which sutures 2610 can be passed andthen wrapped around the respective commissure portion 2608, therebysecuring each commissure tip to each respective commissure portion 2608.Other suitable means of attachment can also be used. The leaflet supportstent 2600 can have a reduced thickness as compared to conventionaldevices. For example, some embodiments of the leaflet support stent 2600can be configured to have at least about a 1 mm lower profile thanconventional devices. In some embodiments, while a conventional flexiblesupport valve may have a thickness of around 1.5 mm, currently disclosedembodiments of a leaflet support valve 2600 can allow for a reducedthickness of around 0.5 mm. For example, the leaflet support stent 2600can be formed from a wire having a thickness of around 0.5 mm. When thevalve portion of a prosthetic heart valve is positioned on top of theleaflet support stent 2600, the overall height of the prosthetic valvecan therefore be reduced by around 1 mm as compared to the height of theoverall prosthetic valve that includes a typical conventional stentinstead.

While the commissure tips 2604 are shown positioned on the inside of thestent frame 2602, they can alternatively be positioned on the outside ofthe stent frame 2602. In alternative embodiments, similar commissuretips can be configured to be positioned on top of the commissureportions 2608, and thus neither inside nor outside the stent frame 2602.In some embodiments, the commissure tips can be formed integrally withthe stent frame. The commissure tips 2604 can be secured to the stentframe 2602 such that the commissure tips 2604 are substantiallyprevented from moving in the axial direction with respect to the stentframe 2602. However, the coupling of the commissure tips 2604 to thecommissure portions 2608 can be configured so as not to interfere withthe radial collapsibility of the overall leaflet support stent 2600.

The leaflet support stent 2600 can be combined with a sealing ring(e.g., sealing ring 880 shown in FIG. 30) and covered in cloth 2730 asdescribed above to form a collapsible stent subassembly 2700, seen inFIG. 41. As shown in FIG. 41, the cloth-covered stent frame 2602′, thecloth-covered commissure tips 2604′, and the cloth-covered sealing ring880′ form the collapsible stent subassembly 2700.

FIG. 42 shows the subassembly 2700 in a radially collapsedconfiguration. Some embodiments of the subassembly 2700 can be radiallycompressed to a relatively smaller diameter than the polymer stent ofFIGS. 28-29, as shown, and return to its expanded, unstressedconfiguration shown in FIG. 41 when any external crimping restraint isremoved. When the subassembly 2700 is radially compressed, thecloth-covered commissure posts 2604′ can remain substantially vertical(e.g., substantially parallel to the axial direction of the leafletsupport stent) such that they do not interfere with the radialcompressibility of the subassembly 2700. Thus, the subassembly 2700 canbe combined with a collapsible wireform and stent portion as describedherein to form a fully collapsible prosthetic heart valve. In someembodiments, the leaflet support stent 2600 and/or subassembly 2700 canbe combined with (e.g., coupled to) a standalone surgical prostheticvalve or wireform portion that does not include a lower stent portionand is configured to be sutured to a patient's native valve. One suchsurgical prosthetic valve is disclosed in the Cao application (US2011-0276128), which is incorporated herein by reference. The use of adisclosed embodiment of the leaflet support stent 2600 with suchsurgical prosthetic valves as disclosed in the Cao application can allowfor use of a minimal size surgical incision when implanting suchsurgical valves.

FIG. 32 shows a wireform 904 partially covered by a cloth frame cover945. Opposing ends of a strip of cloth 945 can be brought together toform a butt joint 947. Adjacent the butt joint 947, opposinglongitudinal edges 948, 949 of the cloth 945 can be wrapped around acusp portion 914 of the wireform 904 and brought into opposing alignmentwith each other to form a seam 946 with the opposing edges. The seam 946can be completed by suturing, or other well-known cloth-edge joiningtechniques. The cloth 945 can be wrapped around the entire wireform 904as just described to arrive at the cloth-covered wireform 904′ shown inFIG. 33. Cloth covers can be formed of any biocompatible fabric, suchas, for example, polyethylene terephthalate. Other covering techniquesare disclosed in U.S. Pat. No. 7,473,275, which is incorporated hereinin its entirety.

Similar to the bare wireform 904, the cloth-covered wireform 904′comprises cusp regions 914′ separated by commissure support portions916.′ Each commissure portion 916′ extends from respective adjacentcusps 914′ to respective distal ends joined to each other by an arcuatecommissure tip.

FIG. 34 shows the cloth covered wireform 904′ of FIG. 33, with threeleaflets 2028 positioned within the wireform. Each leaflet 2028 includestwo tabs 2032 positioned on opposing ends of the leaflet. Eachrespective tab 2032 can be aligned with a tab 2032 of an adjacentleaflet, as shown. Each pair of aligned tabs 2032 can be insertedbetween adjacent extensions of the wireform portion 904′, near thecommissure supports 916.′ The tabs 2032 can then be wrapped around arespective post 1476 of a cloth covered flexible stent (e.g., flexiblestent 1470 of FIG. 28 or the leaflet support stent 2600 of FIGS. 40-42).The tabs 2032 can be sutured or otherwise coupled to each other and/orto the post 1476. In this way, the leaflets 2028, the cloth coveredwireform portion 904′ and the cloth covered flexible stent/sealing ringsubassembly (e.g., subassembly 1700 of FIG. 31 or subassembly 2700 ofFIG. 41) can be coupled together. Coupling the leaflets together in thismanner can position the suture securing the leaflets (e.g., a weak pointof the valve) away from the greatest stresses due to physiologicloading, thereby minimizing the risk of leaflet failure at the suturepoint.

As shown in FIG. 35, the flexible stent and sealing ring subassembly1700 (or subassembly 2700) as described above can be coupled to thesubassembly comprising the cloth covered wireform portion 904′ andcorresponding leaflets 2028 to form a valve portion 2105 of the valve.In alternative embodiments, the leaflet support stent and sealing ringsubassembly 2700 as described above can be used instead of the flexiblestent subassembly 1700 to form the valve portion 2105. This combinationcan create a fully collapsible prosthetic heart valve.

The valve portion 2105 shown in FIG. 35 can be coupled to a stentportion (e.g., stent portion 602 of FIG. 19) to assemble a prostheticvalve. For example, the sealing ring 880 can be sutured to the stentportion, such as to circular openings of vertical struts adjacent thewireform portion. The subassembly 1700 (FIG. 31) or 2700 (FIG. 41) canmatingly engage a corresponding contour of the covered wireform portion904′. In other words, as shown, for example, in FIG. 35, thecloth-covered posts 1476 of the subassembly 1700 (or the cloth-coveredcommissure posts 2604′ of subassembly 2700) can be so sized and shapedas to overlie, or be inserted within, corresponding commissure portions916′ of the wireform 904′. Once in position, the cloth covering theposts 1476 and flexible stent 1470 can be sutured to the cloth covering945 of the wireform 904′. Similarly, in embodiments includingsubassembly 2700, the cloth 2730 covering posts 2604 can be sutured tothe cloth covering 945 of the wireform 904′. In addition, if desired,covers 1495 can be positioned over the exposed portions of thecommissure tabs 2032 of the leaflets 2028, and secured in place withsutures 2196. The covers can be formed of any suitable biocompatiblefabric or polymer.

As shown in FIGS. 34-35, leaflets can be attached to disclosedembodiments of a collapsible prosthetic heart valve in ways similar toleaflet attachment for conventional surgical valves. However, thedisclosed embodiments can allow for radial compression of the prostheticheart valve, unlike surgical valves. For example, due to thecollapsibility of the individual components (e.g., the wireform portion,the leaflet support stent, the sealing ring, and the leaflets) as wellas the methods of attachment, the entire valve portion 2105 can becollapsible to a collapsed state or configuration for delivery.

Delivery Methods

Disclosed embodiments of prosthetic heart valves utilizing one-piece ortwo-piece valve frames can be delivered to a patient's native valveannulus in a number of different ways. For example, in embodiments wherethe frame comprises a superelastic material, the frame can be shape setin the expanded configuration, and radially crimped (e.g., transformedinto a compressed configuration and constrained within a sheath orsimilar structure) for delivery. Some embodiments can be delivered to apatient's valve through a small incision (e.g., a thoracotomy) and asmall aortotomy. Once positioned in or near the implantation site (e.g.,patient's native aortic valve annulus), the sheath can be removed, thusallowing the frame to expand to the expanded configuration (e.g., theframe can expand to the configuration shape-set before implantation).Alternatively, in embodiments with no sheath constraining the wireformportion, expansion of the stent portion (e.g., by inflating a balloon)will allow for expansion of the wireform portion as it follows the stentportion.

In embodiments where the frame comprises a non-superelastic material,the frame can be compressed or collapsed to a collapsed deliveryconfiguration (e.g., the compressed configuration) for introduction intoa patient's body. The collapsed valve can be inserted through anincision in a body lumen at an implantation site (e.g., a patient'snative aortic valve annulus). The valve can then be expanded, such as bya balloon or other mechanism, once positioned in or near the nativevalve annulus. For example, the prosthetic valve can be crimped on adelivery catheter for delivery, positioned at the target site, andexpanded by a balloon such that the stent portion anchors the prostheticvalve in place. In some embodiments, one or more sutures can be used tosecure the valve in place at the implantation site. In some embodiments,no sutures are needed to secure the prosthetic valve. In someembodiments, the prosthetic valve can be positioned such that a sealingring and/or leaflet cusps engage with the shelf of the native annulus.In some embodiments, the prosthetic valve can be radially compressedenough for transapical delivery, and thus can be delivered in a mannersimilar to conventional transcatheter heart valves.

By way of example, FIGS. 36-39 illustrate various stages of implantationof one embodiment of a two-piece prosthetic valve frame 601, shown in asimplified form. The two-piece frame 601 includes a plasticallyexpandable stent portion 602 and a self-expandable wireform portion 604made of different materials which can be coupled together via one ormore non-metallic components (not shown) as described above. Forclarity, the frame 601 is illustrated without leaflets and othercomponents of the valve discussed above. FIG. 36 shows the frame 601 ina collapsed configuration, positioned on a delivery device 603 (e.g., adelivery catheter having an inflatable balloon).

In the embodiment shown in FIG. 36, the stent portion 602 has beencollapsed into a substantially conical configuration, where the diameterof the stent portion 602 adjacent the inflow end 610 is less than thediameter of the stent portion 602 adjacent the circumferential strut 620(e.g., opposite the inflow end 610; adjacent the wireform portion 604).Thus, adjacent vertical struts 622 are closer to one another near theinflow end than they are at the opposite end of the stent portion 602,near the wireform portion 604. The commissure supports 616 of thewireform portion 604 are shown to be compressed more in the radialdirection than are the cusps 614. The wireform portion 604 can be heldin this position by an external restraining sheath, valve holder,sutures, or other suitable techniques or mechanisms. As shown in FIGS.36-38, in some embodiments, a suture 617 can be positioned to hold thecommissure supports 616 in a radially compressed configuration.Alternatively or additionally, the wireform portion can be held in thiscompressed configuration due to its coupling to the stent portion 602.In addition, the stent portion 602 can be stiff enough to retain itscompressed configuration despite any expansion force applied to it bythe wireform portion 604.

Once positioned at or near the implantation site, the frame 601 can thenbe expanded, such as by an inflatable balloon or other mechanism. FIG.37 illustrates partial inflation of the balloon 603. As compared to FIG.36, the stent portion 602 has been expanded adjacent the inflow end 610,but the configuration of the circumferential strut 620 and the wireformportion 604 are substantially the same as in the delivery configurationshown in FIG. 36.

FIG. 38 shows further expansion of the balloon 603. In FIG. 38, thestent portion 602 has reached full expansion at both the inflow end 610and adjacent the circumferential strut 620, yet the commissure supports616 can be still at least partially compressed adjacent the outflow end612. In some embodiments, when the circumferential strut 620 is fullyexpanded, the circumferential strut 620 can have an essentially flatside profile. For example, rather than being pinched into V-shapedsections as shown in FIG. 23, the circumferential strut can appearsubstantially straight when viewed from a side elevation in the expandedconfiguration.

FIG. 39 shows the final expanded configuration of frame 601. Forexample, in some embodiments, a sheath and/or the suture 617 can beremoved (e.g., by cutting or pulling the suture) from the commissuresupports 616 in order to allow the wireform portion to fully self-expandas shown in FIG. 39. In some embodiments, a valve holder on the deliverysystem can be used to hold the commissure supports 616 in a collapsedconfiguration, and the commissure supports 616 can be released from thevalve holder by cutting one or more sutures 617 or by some other releasemechanism. In embodiments where a sheath is used to restrain theprosthetic valve, the sheath first can be partially withdrawn to allowexpansion of the stent portion 602 (FIGS. 37-38), and then fullywithdrawn to allow expansion of the wireform portion 604, includingcommissure supports 616 (FIG. 39).

In some embodiments, the stent portion 602 can be expanded an amountsufficient to anchor the prosthetic valve in place. For example, theframe 601 can be expanded until the stent portion 602 engages thepatient's native valve annulus. In some embodiments, the stent portion602 can exert force radially outward against the native valve annulus,thereby securing the prosthetic valve in place. In some embodiments, atleast a portion of the prosthetic valve can be positionedsupraannularly. For example, as shown in FIG. 20, a sealing ring portion646 can be positioned supraannularly, such that it rests on the shelf653, thereby preventing the valve from migrating into the ventricle 650.

In some embodiments, one or more sutures can be used to secure theprosthetic valve in place at the implantation site. In some embodiments,no sutures are needed to secure the prosthetic valve. In someembodiments, the prosthetic valve can be positioned such that a sealingring and/or leaflet cusps engage with the shelf of the native annulus.In some embodiments, the prosthetic valve can be radially compressedenough for transapical delivery, and thus can be delivered in a mannersimilar to conventional transcatheter heart valves.

Manufacturing Methods

Methods of making and delivering a prosthetic heart valve using aone-piece or two-piece valve frame are also disclosed. For example, inone method, any of the disclosed embodiments of a prosthetic heart valveframe can be provided and at least one valve leaflet can be secured tothe prosthetic heart valve. For example, the at least one valve leafletcan be secured to a one-piece prosthetic heart valve frame by passing afirst and second leaflet tab between the upright strut and the wireformportion, and securing the first and second leaflet tabs to each other.Other methods of leaflet attachment for different valve frame types(e.g., frames without upright struts) are discussed above. A flexibleskirt can also be secured to the stent portion, the flexible skirt beingconfigured to prevent leakage through the stent portion.

In some methods of making a prosthetic heart valve frame, the frame canbe manufactured in two pieces (e.g., the stent portion and the wireformportion can be manufactured separately), and the two pieces can besubsequently joined together, such as by crimping, welding, and/or othermethods of coupling or securing together. In other embodiments, theprosthetic heart valve frame can be made as a single piece. In stillother embodiments, the valve frame can be manufactured in two pieces andnot joined together, other than by the other components of the valve(e.g., the sealing ring, flexible skirt, and/or cloth covering). Forexample, the stent portion and the wireform portion can be coupled toone another during assembly using, for example, cloth and/or sutures(e.g., sutures through the holes in the tops of upright struts).

The frame can be cut (e.g., laser cut, stamped, water-jet cut, oretched) from a sheet of material or from a hollow, metal tube ofsuitable material, such as Nitinol. In some embodiments, the wireformportion can be formed from a wire that has been shaped, with the twoends crimped, welded, or otherwise joined together. In some embodiments,the stent portion can be laser cut from tubing of a desire deliverydiameter (e.g., pre-crimped). For example, the stent portion can be cutfrom 14 mm outer diameter stainless steel tubing, and in this way wouldbe pre-crimped for delivery. In other words, in some embodiments, thestent portion can be cut or formed in its crimped or collapsedconfiguration. In some embodiments, the stent portion can be cut orformed in an expanded or pre-crimped configuration and then furthercrimped for delivery. In some embodiments, the stent portion can becrimped into a substantially conical shape for delivery. The stentportion and the wireform portion can be coupled to one another duringassembly using, for example, cloth and/or sutures.

Generally, any method of forming a prosthetic heart valve frame orcoupling the stent portion and wireform portion together to form aprosthetic heart valve frame can be suitable, as long as collapsibilityof the prosthetic heart valve is retained. The valve frame can also beheat treated in some embodiments to, for example, form a flare at theinflow end of the stent portion. Other finishing processes can also beperformed, such as microblasting and/or electropolishing.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting the scope of the invention. Rather, thescope of the invention is defined by the following claims. I thereforeclaim as our invention all that comes within the scope and spirit ofthese claims.

What is claimed is:
 1. A method of implanting a flexible prostheticheart valve, comprising: radially compressing a prosthetic heart valveto a compressed configuration, wherein the prosthetic heart valvecomprises a valve portion formed by a self-expanding leaflet-supportingstructure and flexible leaflets supported thereby and aplastically-expandable stent portion connected to and extending from aninflow end of the leaflet-supporting structure, the stent portion beingconfigured to anchor the prosthetic heart valve to a patient's nativevalve annulus; delivering the compressed prosthetic heart valve to ornear a patient's native valve annulus; positioning theleaflet-supporting structure of the prosthetic heart valve on a firstside of a patient's native valve annulus and the stent portion on asecond side opposite the first side; and expanding the prosthetic heartvalve to an expanded configuration, wherein in the compressedconfiguration at least an inflow portion of the leaflet-supportingstructure is positioned within a lumen of the stent portion, and in theexpanded configuration the inflow portion of the leaflet-supportingstructure is positioned externally to the lumen of the stent portion soas to rest on the first side of the annulus and present an impediment tothe valve migrating through the annulus in a first direction, andwherein the stent portion expands into contact with the second side ofthe annulus and presents an impediment to the valve migrating throughthe annulus in a second direction opposite the first direction.
 2. Themethod according to claim 1, wherein the prosthetic heart valve includesa one-piece prosthetic heart valve frame.
 3. The method according toclaim 2, wherein expanding the prosthetic heart valve effectivelyanchors the prosthetic heart valve without suturing the valve to thenative valve.
 4. The method according to claim 1, wherein theleaflet-supporting structure of the prosthetic heart valve includes awireform having alternating arcuate cusps on an inflow end thereof andupstanding commissures projecting toward an outflow end thereof togetherdefining an undulating structure, and wherein the flexible leafletsattach along the undulating structure of the wireform, and wherein inthe compressed configuration the inflow portion of theleaflet-supporting structure positioned within the lumen of the stentportion are the cusps of the wireform, and in the expanded configurationthe cusps of the wireform are positioned externally to the lumen of thestent portion.
 5. The method according to claim 1, wherein theleaflet-supporting structure of the prosthetic heart valve includes acloth covered wireform to which a cloth covered flexible stent and outersealing ring subassembly is coupled, the sealing ring being alsopositioned on the first side of the annulus when the valve is expandedand presents an impediment to the valve migrating through the annulus ina first direction.
 6. The method according to claim 1, wherein the stentportion comprises a number of vertical struts connected by a pluralityof circumferentially-extending and radially expandable struts includinga first circumferential strut closest to the inflow end of theleaflet-supporting structure, and the stent portion connects to the aninflow end of the leaflet-supporting structure via connecting suturesthreaded around the circumferential strut.
 7. The method according toclaim 6, wherein the first circumferential strut comprises a pluralityof circular openings through which the connecting sutures thread andsegments between the circular openings that are pinched into V-shapedsections in the compressed configuration of the stent portion and whichstraighten out in the expanded configuration.
 8. The method according toclaim 1, wherein the stent portion comprises a number of vertical strutsconnected by a plurality of circumferentially-extending and radiallyexpandable struts, and wherein different rows ofcircumferentially-extending struts are configured to expand differentamounts so that the stent portion flares outwards toward its inflow endwhen expanded.
 9. The method according to claim 1, wherein theleaflet-supporting structure of the prosthetic heart valve includes awireform formed of a superelastic material chosen from the groupconsisting of Nitinol, NiTiCo, NiTiCr, and alloys thereof, and the stentportion of the prosthetic heart valve is formed of a plasticallydeformable material chosen from the group consisting of stainless steel,cobalt, chromium, titanium, and alloys thereof.
 10. The method accordingto claim 1, wherein the stent portion has sufficient rigidity tomaintain the inflow end of the leaflet-supporting structure in itscompressed configuration while an outflow end of the leaflet-supportingstructure is held in a compressed configuration by an external restraintand the step of expanding the prosthetic heart valve to an expandedconfiguration includes removing the external restraint.
 11. A method ofimplanting a flexible prosthetic heart valve, comprising: radiallycompressing a prosthetic heart valve to a compressed configuration,wherein the prosthetic heart valve comprises a plastically-deformablestent portion on an inflow end configured to anchor the prosthetic heartvalve to a patient's native valve annulus and a self-expandingleaflet-supporting structure on an outflow end and flexible leafletssupported thereby, the stent portion and leaflet-supporting structurebeing connected in series and the stent portion having sufficientrigidity to maintain the inflow end of the leaflet-supporting structurein its compressed configuration while an outflow end of theleaflet-supporting structure is held in a compressed configuration by anexternal restraint; delivering the compressed prosthetic heart valve toa patient's native valve annulus; positioning the leaflet-supportingstructure of the prosthetic heart valve on a first side of a patient'snative valve annulus and the stent portion on a second side opposite thefirst side; plastically expanding the stent portion outward into contactwith surrounding anatomical structure; and removing the externalrestraint to permit the outflow end of the leaflet-supporting structureto self-expand outward into contact with surrounding anatomicalstructure.
 12. The method according to claim 11, wherein theleaflet-supporting structure includes a wireform having alternatingarcuate cusps on an inflow end thereof and upstanding commissuresprojecting toward an outflow end thereof together defining an undulatingstructure, and wherein the flexible leaflets attach along the undulatingstructure of the wireform, and wherein when compressed the cusps of thewireform are positioned within the lumen of the stent portion, and whenexpanded the cusps of the wireform are positioned externally to thelumen of the stent portion.
 13. The method according to claim 11,wherein the leaflet-supporting structure includes a wireform formed of asuperelastic material that is shape set to an expanded configuration,and radially crimped and held in a compressed configuration by theexternal restraint for delivery, and the external restraint is selectedfrom the group consisting of a sheath, a valve holder, and at least onesuture.
 14. The method according to claim 11, wherein theleaflet-supporting structure includes a wireform having alternatingarcuate cusps on an inflow end thereof and upstanding commissuresprojecting toward an outflow end thereof together defining an undulatingstructure, and the external restraint is at least one suture threadedthrough the commissure supports and tensioned to hold them in thecompressed configuration.
 15. The method according to claim 11, whereinthe step of delivering the compressed prosthetic heart valve to apatient's native valve annulus includes delivering the compressedprosthetic heart valve through a thoracotomy and a small aortotomy. 16.The method according to claim 11, wherein the leaflet-supportingstructure of the prosthetic heart valve includes a cloth coveredwireform to which a cloth covered flexible stent and outer sealing ringsubassembly is coupled.
 17. The method according to claim 11, whereinthe stent portion comprises a number of vertical struts connected by aplurality of circumferentially-extending and radially expandable strutsincluding a first circumferential strut closest to the inflow end of theleaflet-supporting structure, and the stent portion connects to the aninflow end of the leaflet-supporting structure via connecting suturesthreaded around the circumferential strut.
 18. The method according toclaim 17, wherein the first circumferential strut comprises a pluralityof circular openings through which the connecting sutures thread andsegments between the circular openings that are pinched into V-shapedsections in the compressed configuration of the stent portion and whichstraighten out in the expanded configuration.
 19. The method accordingto claim 11, wherein the stent portion comprises a number of verticalstruts connected by a plurality of circumferentially-extending andradially expandable struts, and wherein different rows ofcircumferentially-extending struts are configured to expand differentamounts so that the stent portion flares outwards toward its inflow endwhen expanded.
 20. The method according to claim 11, wherein theleaflet-supporting structure of the prosthetic heart valve includes awireform formed of a superelastic material chosen from the groupconsisting of Nitinol, NiTiCo, NiTiCr, and alloys thereof, and the stentportion of the prosthetic heart valve is formed of a plasticallydeformable material chosen from the group consisting of stainless steel,cobalt, chromium, titanium, and alloys thereof.